Pharmacogenomics Implications of Using Herbal Medicinal Plants on African Populations in Health Transition

A scoping review on the use of traditional medicine and oral health in Africa

BACKGROUND

This review aimed to chart the landscape of literature concerning the precise applications of traditional medicine in managing specific oral diseases and, in doing so, to pinpoint knowledge gaps surrounding the use of traditional medicine for oral disease management in the African context.

METHODS

A systematic search of the literature was conducted on PubMed, Web of Science, Scopus, and CINAHL. The search was conducted from the inception of the database till September 2023. A search of related citations and references was also carried out. Only English language publications were included. A summary of studies that met the inclusion criteria was conducted.

RESULTS

Of the 584 records identified, 11 were duplicates and 12 studies, published between 2006 and 2021, met the inclusion criteria. The studies were published from eight countries located in the five sub-regions on the continent. All the studies were either experimental designs or ethnobotanical surveys and they all utilized plant-based remedies. The five experimental studies aimed to assess the impact of whole plants or plant extracts on the three microorganisms responsible for dental caries and seven responsible for periodontal diseases. The number of plant species identified by the seven ethnobotanical surveys ranged from 29 to 62 while the number of plan families ranged from 15 to 29. The remedies were either topical applied, use as mouth rinses, gargled, or chewed. The systemic routes of administration identified were inhalation and drinking. The remedies were used for the treatment of hard such as dental caries and tooth sensitivity, to soft tissue lesions such as mouth ulcers, gingival bleeding, and mouth thrush. Other oral disorders managed include halitosis, jaw fracture, and oral cancer.

CONCLUSIONS

Given the increasing prevalence of oral diseases within the region, the shortage of oral healthcare professionals and limited access to financial resources, it becomes imperative to support the generation of empirical evidence to enhance the provision of traditional medicine for oral healthcare in Africa.

Nanoparticle elicitation: A promising strategy to modulate the production of bioactive compounds in hairy roots

Hairy root culture is one of the promising biotechnological tools to obtain the stable and sustainable production of specialized metabolites from plants under controlled environment conditions. Various strategies have been adopted to enhance the accumulation of bioactive compounds in hairy roots yet their utilization at the commercial scale is restricted to only a few products. Recently, nanotechnology has been emerged as an active technique that has revolutionized the many sectors in an advantageous way. Elicitation using nanoparticles has been recognized as an effective strategy for enhancing the bioactive compounds of interest in plants. Nanoparticles elicit the activity of defense-related compounds through activation of the specific transcription factors involved in specialized metabolites production. This review discusses the recent progress in using nanoparticles to enhance specialized metabolite biosynthesis using hairy root culture system and the significant achievements in this area of research. Biotic and abiotic elicitors to improve the production of bioactive compounds in hairy roots, different types of nanoparticles as eliciting agents, their properties as dependent on shape, most widely used nanoparticles in plant hairy root systems are described in detail. Further challenges involved in application of nanoparticles, their toxicity in plant cells and risks associated to human health are also envisaged. No doubt, nanoparticle elicitation is a remarkable approach to obtain phytochemicals from hairy roots to be utilized in various sectors including food, medicines, cosmetics or agriculture but it is quite essential to understand the inter-relationships between the nanoparticles and the plant systems in terms of specifics such as type, dosage and time of exposure as well as other important parameters.

Changing Trends Towards Herbal Supplements: An Insight into Safety and Herb-drug Interaction

Herbs have been used as sustenance and medicine for a very long time, often in conjunction with other prescribed medications. Even though they are thought to be natural and secure, many of these herbs can interact with other medications and cause potentially dangerous adverse effects or decrease the benefits of the medication. The complex and diverse pharmacological functions carried out by the active ingredients in herbs unavoidably alter the pharmacokinetics of chemical drugs when administered in vivo. Drug transporter expression has a direct impact on how medications are absorbed, distributed, metabolized, and excreted in living organisms. Changes in substrate pharmacokinetics can affect the effectiveness and toxicity of a drug when the active ingredients of a herb inhibit or stimulate the expression of transporters. By reviewing published clinical and preclinical studies, this review aims to raise awareness of herbdrug interactions and discuss their evidence-based mechanisms and clinical consequences. More clinical information on herb-drug interactions is required to make choices regarding patient safety as the incidence and severity of herb-drug interactions are rising due to an increase in the use of herbal preparations globally.This review seeks to increase understanding of herb-drug interactions and explore their evidence-based mechanisms and clinical implications by reviewing published clinical and preclinical studies. The incidence and severity of herb-drug interactions are on the rise due to an increase in the use of herbal preparations worldwide, necessitating the need for more clinical data on these interactions in order to make decisions regarding patient safety. Healthcare workers and patients will become more alert to potential interactions as their knowledge of pharmacokinetic herb-drug interactions grows. The study's objective is to raise readers' awareness of possible interactions between herbal supplements and prescription medications who regularly take them.

The Main Medicinal Plants in Arid Regions of Uzbekistan and Their Traditional Use in Folk Medicine

Seventy percent of the territory of Uzbekistan consists of arid regions. This situation is considered very favorable for plants adapted to a desert climate. Medicinal plants distributed in the arid regions of Uzbekistan have not been studied much. Medicinal plants are considered inexpensive, yet are vital for the lives of local residents. They play a very important role in the traditional healing of ailments. To determine the current state of medicinal plants and enhance their subsequent protection and sustainable use, it is necessary to obtain annual information on the state of their distribution, their population size, and the impact of negative factors on their populations. Based on our field studies, which were conducted during the period from 2012 to 2022 in the arid regions of Uzbekistan, we updated the checklists of the main medicinal plants used in these regions. A total of 529 medicinal species belonging to 70 families and 269 genera were identified in the study region. Several species, including Peganum harmala L., Capparis spinosa L., Ferula foetida (Bunge) Regel, Glycyrrhiza glabra L., Alhagi pseudalhagi (M. Bieb.) Desv. ex Wangerin, Lagochilus inebrians Bunge, Xanthium strumarium L., Silybum marianum (L.) Gaertn., Onopordum acanthium L., Ziziphora tenuior L., and Cichorium intybus L., are spread over large areas and have been used regularly by the locals since ancient times. These species are common in saline and degraded soils in arid regions of Uzbekistan. Semi-structured interviews were conducted with tabibs (traditional doctors), elders, herders, and residents with experience in traditional healing using medicinal plants. The medicinal value of most plants was based on the interviews with representatives of the local population, which were useful for understanding traditional healing skills and customer service skills.

Pharmacogenomics of Hypertension in Africa: Paving the Way for a Pharmacogenetic-Based Approach for the Treatment of Hypertension in Africans

In Africa, the burden of hypertension has been rising at an alarming rate for the last two decades and is a major cause for cardiovascular disease (CVD) mortality and morbidity. Hypertension is characterised by elevated blood pressure (BP) ≥ 140/90 mmHg. Current hypertension guidelines recommend the use of antihypertensives belonging to the following classes: calcium channel blockers (CCB), angiotensin converting inhibitors (ACEI), angiotensin receptor blockers (ARB), diuretics, β-blockers, and mineralocorticoid receptor antagonists (MRAs), to manage hypertension. Still, a considerable number of hypertensives in Africa have their BP uncontrolled due to poor drug response and remain at the risk of CVD events. Genetic factors are a major contributing factor, accounting for 20% to 80% of individual variability in therapy and poor response. Poor response to antihypertensive drug therapy is characterised by elevated BPs and occurrence of adverse drug reactions (ADRs). As a result, there have been numerous studies which have examined the role of genetic variation and its influence on antihypertensive drug response. These studies are predominantly carried out in non-African populations, including Europeans and Asians, with few or no Africans participating. It is important to note that the greatest genetic diversity is observed in African populations as well as the highest prevalence of hypertension. As a result, this warrants a need to focus on how genetic variation affects response to therapeutic interventions used to manage hypertension in African populations. In this paper, we discuss the implications of genetic diversity in CYP11B2, GRK4, NEDD4L, NPPA, SCNN1B, UMOD, CYP411, WNK, CYP3A4/5, ACE, ADBR1/2, GNB3, NOS3, B2, BEST3, SLC25A31, LRRC15 genes, and chromosome 12q loci on hypertension susceptibility and response to antihypertensive therapy. We show that African populations are poorly explored genetically, and for the few characterised genes, they exhibit qualitative and quantitative differences in the profile of pharmacogene variants when compared to other ethnic groups. We conclude by proposing prioritization of pharmacogenetics research in Africa and possible adoption of pharmacogenetic-guided therapies for hypertension in African patients. Finally, we outline the implications, challenges, and opportunities these studies present for populations of non-European descent.

Phytochemical and Biological Investigation of an Indigenous Plant of Bangladesh, Gynura procumbens (Lour.) Merr.: Drug Discovery from Nature

Gynura procumbens (Lour.) Merr. (Family: Asteraceae) is a tropical Asian medicinal plant found in Thailand, China, Malaysia, Indonesia, and Vietnam. It has long been utilized to treat a variety of health concerns in numerous countries around the world, such as renal discomfort, constipation, diabetes mellitus, rheumatism, and hypertension. The chemical investigation resulted in the isolation and characterization of six compounds from the methanol (MeOH) extract of the leaves of Gynura procumbens, which were identified as phytol (1), lupeol (2), stigmasterol (3), friedelanol acetate (4), β-amyrin (5), and a mixture of stigmasterol and β-sitosterol (6). In-depth investigations of the high-resolution ¹H NMR and ¹³C NMR spectroscopic data from the isolated compounds, along with comparisons to previously published data, were used to clarify their structures. Among these, the occurrence of Compounds 1 and 4 in this plant are reported for the first time. The crude methanolic extract (CME) and its different partitionates, i.e., petroleum ether (PESF), chloroform (CSF), ethyl acetate (EASF), and aqueous (AQSF) soluble fractions, were subjected to antioxidant, cytotoxic, thrombolytic, and anti-diabetic activities. In a DPPH free radical scavenging assay, EASF showed the maximum activity, with an IC₅₀ value of 10.78 µg/mL. On the other hand, CSF displayed the highest cytotoxic effect with an LC₅₀ value of 1.94 µg/mL compared to 0.464 µg/mL for vincristine sulphate. In a thrombolytic assay, the crude methanolic extract exhibited the highest activity (63.77%) compared to standard streptokinase (70.78%). During the assay for anti-diabetic activity, the PESF showed 70.37% of glucose-lowering activity, where standard glibenclamide showed 63.24% of glucose-reducing activity.

Anti-human immunodeficiency virus-1 activity of MoMo30 protein isolated from the traditional African medicinal plant Momordica balsamina

BACKGROUND

Plants are used in traditional healing practices of many cultures worldwide. Momordica balsamina is a plant commonly used by traditional African healers as a part of a treatment for HIV/AIDS. It is typically given as a tea to patients with HIV/AIDS. Water-soluble extracts of this plant were found to contain anti-HIV activity.

METHODS

We employed cell-based infectivity assays, surface plasmon resonance, and a molecular-cell model of the gp120-CD4 interaction to study the mechanism of action of the MoMo30-plant protein. Using Edman degradation results of the 15 N-terminal amino acids, we determined the gene sequence of the MoMo30-plant protein from an RNAseq library from total RNA extracted from Momordica balsamina.

RESULTS

Here, we identify the active ingredient of water extracts of the leaves of Momordica balsamina as a 30 kDa protein we call MoMo30-plant. We have identified the gene for MoMo30 and found it is homologous to a group of plant lectins known as Hevamine A-like proteins. MoMo30-plant is distinct from other proteins previously reported agents from the Momordica species, such as ribosome-inactivating proteins such as MAP30 and Balsamin. MoMo30-plant binds to gp120 through its glycan groups and functions as a lectin or carbohydrate-binding agent (CBA). It inhibits HIV-1 at nanomolar levels and has minimal cellular toxicity at inhibitory levels.

CONCLUSIONS

CBAs like MoMo30 can bind to glycans on the surface of the enveloped glycoprotein of HIV (gp120) and block entry. Exposure to CBAs has two effects on the virus. First, it blocks infection of susceptible cells. Secondly, MoMo30 drives the selection of viruses with altered glycosylation patterns, potentially altering their immunogenicity. Such an agent could represent a change in the treatment strategy for HIV/AIDS that allows a rapid reduction in viral loads while selecting for an underglycosylated virus, potentially facilitating the host immune response.

Long-term exposure to cimetidine induced gonado-toxicity in male rats: Modulating role of Ocimum gratissimum

BACKGROUND

Available evidence suggests that cimetidine is a reproductive toxicant that induces sexual and testicular dysfunction. Ocimum gratissimum (OG) is globally consumed for medicinal and nutritional purposes. To determine the modulating role of aqueous leaf extract of Ocimum gratissimum on cimetidine-induced gonado-toxicity, sexually mature male rats were randomized into four groups of six (n=6) rats each. Group A: control given 2ml distilled water. Group B received 500mg/kg body weight (bwt) of OG extract, Group C received 50mg/kg bwt cimetidine, and group D received 50mg/kg bwt of cimetidine+500mg/kg bwt OG extract once daily for 8 weeks via gastric gavage. Parameters tested include sperm parameters, testosterone (TT), luteinizing hormone (LH), follicle stimulating hormone (FSH) and prolactin, testicular alkaline phosphatase (ALP), acid phosphatase (ACP), lactate dehydrogenase (LDH), protein, cholesterol, glycogen, sexual behavioural parameters, and testicular histology.

RESULTS

There were depletions in the seminiferous epithelium, decreased sperm quality, TT, LH, and FSH, testicular enzymes, protein, cholesterol, glycogen, and sexual behaviour increase in animals treated with cimetidine only compared to control. OG restored and improved sexual behaviour and libido as evident from increased frequencies of mount, intromission, ejaculation, and ejaculatory latency. Mount latencies, intromission, post-ejaculation, and prolactin were significantly decreased. The significantly decreased testicular activities of ALP, ACP, LDH and protein, cholesterol, glycogen concentrations, TT, LH and FSH were increased by OG administration.

CONCLUSION

Ocimum gratissimum attenuated the deleterious effects of cimetidine on the testis, protected the seminiferous epithelium, restored, and boosted sexual competence, and promoted spermatogenesis.

Coumarin protects Cherax quadricarinatus (red claw crayfish) against white spot syndrome virus infection

Coumarin is a natural compound from plants with the molecular formula C₉H₆O₂. Cherax quadricarinatus (red claw crayfish) is an aquaculture species exhibiting high economic efficiency and quality that is mainly distributed and cultivated in the southeast provinces in China. In order to identify an effective herbal immunopotentiator against white spot syndrome virus (WSSV) infection, this study examined the effect of coumarin as a feed additive in protecting C. quadricarinatus against WSSV infection. The expression of immune-related genes and WSSV copies were analyzed by Q-PCR. Challenge experiments were conducted to analyze the survival rate and determine the optimal concentration of coumarin. The Phenoloxidase activity (PO), Acid phosphatase (ACP) and superoxide dismutase activity (SOD) activity and lysozyme activity were also analyzed. Total hemocyte count (THC) and apoptosis rate were determined by flow cytometry. The WSSV challenge results showed that 40 mg/kg coumarin reduced the mortality of C. quadricarinatus and delayed the WSSV infection process. Further investigation showed that coumarin treatment had a positive effect on the important immunity-related parameters THC, ACP activity, SOD activity, LZM and PO activity. Coumarin up-regulated the expression of proPO, JAK, STAT, ALF, Hsp70 and down-regulated the expression of caspase at the mRNA level. After WSSV infection, the hemocyte apoptosis rate was lower in the 40 mg/kg coumarin + WSSV group compared with the WSSV only group. These data illustrate that coumarin enhances innate immunity in C. quadricarinatus and exhibits a protective effect against WSSV infection by reducing the number of WSSV copies and slowing the process of infection, which provides a potential theoretical basis for studies of coumarin as a new aquatic feed additive in crustacean aquaculture.

Warfarin Pharmacogenomics for Precision Medicine in Real-Life Clinical Practice in Southern Africa: Harnessing 73 Variants in 29 Pharmacogenes

Pharmacogenomics is universally relevant for worldwide modern therapeutics and yet needs further development in resource-limited countries. While there is an abundance of genetic association studies in controlled medical settings, there is a paucity of studies with a naturalistic design in real-life clinical practice in patients with comorbidities and under multiple drug treatment regimens. African patients are often burdened with communicable and noncommunicable comorbidities, yet the application of pharmacogenomics in African clinical settings remains limited. Using warfarin as a model, this study aims at minimizing gaps in precision/personalized medicine research in African clinical practice. We present, therefore, pharmacogenomic profiles of a cohort of 503 black Africans (n = 252) and Mixed Ancestry (n = 251) patients from Southern Africa, on warfarin and co-prescribed drugs in a naturalized noncontrolled environment. Seventy-three (n = 73) single nucleotide polymorphisms (SNPs) in 29 pharmacogenes were characterized using a combination of allelic discrimination, Sanger sequencing, restriction fragment length polymorphism, and Sequenom Mass Array. The common comorbidities were hypertension (43-46%), heart failure (39-45%), diabetes mellitus (18%), arrhythmia (25%), and HIV infection (15%). Accordingly, the most common co-prescribed drugs were antihypertensives, antiarrhythmic drugs, antidiabetics, and antiretroviral therapy. We observed marked variation in major pharmacogenes both at interethnic levels and within African subpopulations. The Mixed Ancestry group presented a profile of genetic variants reflecting their European, Asian, and African admixture. Precision medicine requires that African populations begin to capture their own pharmacogenetic SNPs as they cannot always infer with absolute certainty from Asian and European populations. In the current historical moment of the COVID-19 pandemic, we also underscore that the spectrum of drugs interacting with warfarin will likely increase, given the systemic and cardiovascular effects of COVID-19, and the anticipated influx of COVID-19 medicines in the near future. This observational clinical pharmacogenomics study of warfarin, together with past precision medicine research, collectively, lends strong support for incorporation of pharmacogenetic profiling in clinical settings in African patients for effective and safe administration of therapeutics.

Phytochemical screening, phenolic and flavonoid contents, antioxidant and cytogenotoxicity activities of Combretum leprosum Mart. (Combretaceae)

Combretum leprosum Mart. (Combretaceae), a shrub popularly known as mofumbo, is used in folk medicine for treatment of uterine bleeding, pertussis, gastric pain, and as a sedative. The aim of this study was to (1) determine the phytochemical profile,(2) identify chemical constituents and (3) examine antioxidant and cytogenotoxic activity of ethanolic extracts and fractions of stem bark and leaves. The plant material (leaf and stem bark) was submitted to extraction with ethanol, followed by partition using hexane, chloroform, and ethyl acetate. It was possible to identify and quantify the epicatechin in the ethanolic stem bark extract (0.065 mg/g extract) and rutin in the leaf extract (3.33 mg/g extract). Based upon in vitro tests a significant relationship was noted between findings from antioxidant tests and levels of total phenolic and flavonoid. Comparing all samples (extracts and fractions), the ethyl acetate fractions of stem bark (411.40 ± 15.38 GAE/g) and leaves (225.49 ± 9.47 GAE/g) exhibited higher phenolic content, whereas hexanic fraction of stem bark (124.28 ± 56 mg/g sample) and ethyl acetate fraction of leaves (238.91 ± 1.73 mg/g sample) demonstrated a higher content of flavonoids. Among the antioxidant tests, the intermediate fraction of stem bark (28.5 ± 0.60 μg/ml) and ethyl acetate fraction of leaves (40 ± 0.56 μg/ml) displayed a higher % inhibition of free radical DPPH activity, whereas intermediate fraction of stem bark (27.5 ± 0.9 μg/ml) and hydromethanol fraction of leaves (81 ± 1.4 μg/ml) demonstrated inhibition of the free radical ABTS. In biological tests (Allium cepa and micronucleus in peripheral blood), data showed that none of the tested concentrations of ethanolic extracts of leaves and stem bark produced significant cytotoxicity, genotoxicity, and mutagenic activity.Abbreviations AA%: percentage of antioxidant activity; ABTS: 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid); CEUA: Ethics Committee in the Use of Animals; TLC: Thin Layer Chromatography; DNA: deoxyribonucleic acid; DPPH: 1,1-diphenyl-2-picrylhydrazyl; ROS: Reactive oxygen species; EEB: ethanol extract of the stem bark; HFB: Hexanic fraction of stem bark; IFB: Intermediate fraction of stem bark; CFB: Chloroform fraction of stem bark; EAFB: Ethyl acetate fraction of stem bark; HMFB: Hydromethanol fraction of the stem bark; EEL: Ethanol extract from leaves; HFL: Hexane fraction of leaves; CFL: Chloroform fraction of leaves; EAFL: Ethyl acetate fraction of leaves; HMFL: Hydromethanol fraction of leaves; GAE: Gallic Acid Equivalent; IC₅₀: 50% inhibition concentration; HCOOH: Formic acid; HCl: hydrochloric acid; HPLC: High-performance liquid chromatography; MN: micronucleus; WHO: World Health Organization; UFLC: Ultra-Fast Liquid Chromatography; UESPI: State University of Piauí.

Cytochrome P450 Enzyme Inhibition and Herb-Drug Interaction Potential of Medicinal Plant Extracts Used for Management of Diabetes in Nigeria

BACKGROUND AND OBJECTIVE

The use of herbal medicines is common in Africa, and patients often use a combination of herbs and drugs. Concurrent herbal and pharmaceuticals treatments can cause adverse effects through herb-drug interactions (HDI). This study evaluated the potential risk of HDI for five medicinal plants, Vernonia amygdalina, Ocimum gratissimum, Moringa oleifera, Azadirachta indica, and Picralima nitida, using in vitro assays. Patients with diabetes and some other disease conditions commonly use these medicinal plants in Nigeria, and little is known regarding their potential for drug interaction, despite their enormous use.

METHODS

Crude extracts of the medicinal plants were evaluated for reversible and time-dependent inhibition (TDI) activity of six cytochrome P450 (CYP) enzymes using pooled human liver microsomes and cocktail probe-based assays. Enzyme activity was determined by quantifying marker metabolites' formation using liquid chromatography-mass spectrometry/mass spectrometry. The drug interaction potential was predicted for each herbal extract using the in vitro half-maximal inhibitory concentration (IC₅₀) values and the percentage yield.

RESULTS

O. gratissimum methanol extracts reversibly inhibited CYP 1A2, 2C8, 2C9 and 2C19 enzymes (IC₅₀: 6.21 µg/ml, 2.96 µg/ml, 3.33 µg/ml and 1.37 µg/ml, respectively). Additionally, V. amygdalina methanol extract inhibited CYP2C8 activity (IC₅₀: 5.71 µg/ml); P. nitida methanol and aqueous extracts inhibited CYP2D6 activity (IC₅₀: 1.99 µg/ml and 2.36 µg/ml, respectively) while A. indica methanol extract inhibited CYP 3A4/5, 2C8 and 2C9 activity (IC₅₀: 7.31 µg/ml, 9.97 µg/ml and 9.20 µg/ml, respectively). The extracts showed a potential for TDI of the enzymes when incubated at 200 µg/ml; V. amygdalina and A. indica methanol extracts exhibited TDI potential for all the major CYPs.

CONCLUSIONS

The medicinal plants inhibited CYP activity in vitro, with the potential to cause in vivo HDI. Clinical risk assessment and proactive monitoring are recommended for patients who use these medicinal plants concurrently with drugs that are cleared through CYP metabolism.

A comprehensive evaluation of the chemical profiles and biological properties of six geophytes from Turkey: Sources of bioactive compounds for novel nutraceuticals

Geophytes are gaining interest as sources of natural ingredients in nutraceutical and pharmaceutical area. In this sense, six bulbous plant species from Turkey are investigated, namely Hyacinthella campanulata K.Perss. & Wendelbo, Muscari neglectum Guss. ex Ten., Tulipa humilis herb., Iris stenophylla Hausskn. ex Baker, Galanthus elwesii Hook. f. and Crocus danfordiae Maw. with the aim to highlight their chemical compositions and biological properties. Polyphenolic profiles of the different plant parts (flower, bulb and leaf) of the six genotypes were evaluated using colorimetric methods as well LC-MS/MS. The antioxidant properties and enzymes inhibitory potential (α-amylase, α-glucosidase, tyrosinase and cholinesterases) of the extracts were determined. Overall, highest total phenolic content and total flavonoid content were observed in the leaf extracts of the studied species, except for M. neglectum (flower extract) and T. humilis (flower extract). LC-MS/MS analysis revealed the abundance of some phenolic compounds including quinic acid, hesperidin and chlorogenic acid in selective extracts. The extracts showed significant antioxidant potentials, with leaf extract of the I. stenophylla being more potent, which is linked to its high phenolic contents. All the extracts displayed notable anti-acetylcholinesterase (1.77 - 2.53 mg GALAE/g) and tyrosinase (54.9-67.20 mg KAE/g). Selective extracts have showed activity against butyrylcholinesterase, with bulb extract of M. neglectum (2.99 mg GALAE/g), I. stenophylla (2.53 mg GALAE/g) and G. elwesii (2.52 mg GALAE/g) showing highest activity. Modest activity was observed against α-amylase and α-glucosidase. The experimental data gathered herein is the first report on the phytochemical and biological attributes of these bulbous plant species which project them as potential sources of biologically active compounds for phytomedicines and nutraceuticals development.

Nephroprotective effect of persimmon leaves (Diospyros kaki L.f.) against CCl4-induced renal toxicity in Swiss Albino rats

Diospyros kaki L.f. fruit and leaves are traditionally used for the treatment of hypertension, angina, internal hemorrhage, antithrombotic and anti-inflammatory effects.In the current study, the protective effects of ethyl acetate (Per-1), n-butanol (Per-2), and aqueous (Per-3) fractions of Diospyros kaki leaves against carbon tetrachloride (CCl₄) induced nephrotoxicity in Swiss albino rats were tested. Animal were divided into nine groups; each group consists of six animals. The groups were : group I was untreated and kept as control, group II was treated with CCl₄ only, group III (silymarin with CCl₄); group IV (Per-1 100 mg/kg with CCl₄);group V (Per-1 200 mg/kg with CCl₄); group VI (Per-2 100 mg/kg with CCl₄); group VII (Per-2 200 mg/kg with CCl₄); group VIII (Per-3 100 mg/kg with CCl₄); and group IX (Per-3 200 mg/kg with CCl₄). Silymarin was used as standard drug. All tested fractions were found active (except Per-1 at low dose of 100 mg/kg) with significant value (p < 0.001) compared to CCl₄ only group. Serum creatinine, malondialdehyde (MDA), and uric acid were significantly (p < 0.001) lowered in group VII-IX as compared to CCl₄ only group. Similarly, total protein (TP) and non-protein sulfhydryls(NP-SH) level in kidney tissues were significantly (p < 0.001) elevated in the same groups compared to CCl₄ only group. Further to check the cardio-protective potential, biochemical parameters such as LDH, creatine kinase, TP, MDA, and NP-SH levels in myocardial tissues were also estimated.These findings confirmed that the n-butanol and aqueous fractions are active and recommended for further bioactive phytoconstituents screening. Repeated column chromatography on silica gel G and sephadex-LH-20 of the active n-butanol fraction, four flavonoids were isolated. Based on the spectroscopic NMR data, compounds were identified as kaempferol (1), quercetin (2), astragalin (3), and rutin (4).

Potential challenges to sustained viral load suppression in the HIV treatment programme in South Africa: a narrative overview

Background

South Africa, with one of the highest HIV prevalences in the world, introduced the universal test and treat (UTT) programme in September 2016. Barriers to sustained viral suppression may include drug resistance in the pre-treated population, non-adherence, acquired resistance; pharmacokinetics and pharmacodynamics, and concurrent use of alternative treatments.

Objective

The purpose of this review is to highlight potential challenges to achieving sustained viral load suppression in South Africa (SA), a major expectation of the UTT initiative.

Methodology

Through the PRISMA approach, published articles from South Africa on transmitted drug resistance; adherence to ARV; host genetic factors in drug pharmacokinetics and pharmacodynamics, and interactions between ARV and herbal medicine were searched and reviewed.

Results

The level of drug resistance in the pre-treated population in South Africa has increased over the years, although it is heterogeneous across and within Provinces. At least one study has documented a pre-treated population with moderate (> 5%) or high (> 15%) levels of drug resistance in eight of the nine Provinces. The concurrent use of ARV and medicinal herbal preparation is fairly common in SA, and may be impacting negatively on adherence to ARV. Only few studies have investigated the association between the genetically diverse South African population and pharmacokinetics and pharmacodynamics of ARVs.

Conclusion

The increasing levels of drug resistant viruses in the pre-treated population poses a threat to viral load suppression and the sustainability of first line regimens. Drug resistance surveillance systems to track the emergence of resistant viruses, study the burden of prior exposure to ARV and the parallel use of alternative medicines, with the goal of minimizing resistance development and virologic failure are proposed for all the Provinces of South Africa. Optimal management of the different drivers of drug resistance in the pre-treated population, non-adherence, and acquired drug resistance will be beneficial in ensuring sustained viral suppression in at least 90% of those on treatment, a key component of the 90-90-90 strategy.

Effects of extracts and molecules derived from medicinal plants of West Africa in the prevention and treatment of gynecological cancers. A Review

Medicinal plants are a potential source of drug discovery and development of new pharmacological compounds for cancer chemoprevention. More than 80% of the West African population uses medicinal plants. It is estimated that over 60% of approved anti-cancer agents are derived from plants. The plant raw material used in African traditional medicine and particularly in West Africa can be an important source for the research of anti-tumor drugs against gynecological cancers. These tumors have a negative impact on women's general health status and causes enormous health costs as they affect all age groups. Gynecological cancers remain thus a major concern worldwide, especially in West Africa where these cancers are the leading cause of cancer deaths in women. This review reports on the contribution of West African flora to the discovery of potential antiproliferative and/or cytotoxic phytochemical compounds against gynecological cancer cells. Scientific databases such as PubMed, ScienceDirect, Scopus and GoogleScholar were used to extract publications reporting West African plants and/or isolated compounds used in cell models of gynecological cancers. Thresholds of cytotoxicity and modes of action of these phytochemicals have been summarized. This research can serve as a basis for taking medicinal plants into account in the management of these gynecological cancers in resource-limited countries such as those in West Africa.

"There is a Balm in Gilead": Black Social Workers' Spiritual Counterstory on the COVID-19 Crisis

The authors assert that art-based inquiry can serve as a powerful medium for understanding the connection between faith and resilience as perceived and understood by older African-Americans adults disproportionately affected by the COVID-19 pandemic. Utilizing the CRT method of counterstorytelling as our conduit to elucidate our culturally situated responses to the COVID-19 pandemic. We seek to explore the connections between faith and resilience in social work practice during this public health crisis. Drawing from our shared experiences as two Black social workers we discuss the role spirituality plays in mitigating loneliness and stress among socially isolated older African-American adults (i.e., social distancing). Finally, with physical contact limited (i.e., social distancing) because of COVID-19, implications and recommendations for using spiritual-based practices with older African-American adults and families are discussed.

Worldwide Research Trends on Medicinal Plants

The use of medicinal plants has been done since ancient times and may even be considered the origin of modern medicine. Compounds of plant origin have been and still are an important source of compounds for drugs. In this study a bibliometric study of all the works indexed in the Scopus database until 2019 has been carried out, analyzing more than 100,000 publications. On the one hand, the main countries, institutions and authors researching this topic have been identified, as well as their evolution over time. On the other hand, the links between the authors, the countries and the topics under research have been analyzed through the detection of communities. The last two periods, from 2009 to 2014 and from 2015 to 2019, have been examined in terms of research topics. It has been observed that the areas of study or clusters have been reduced, those of the last period being those engaged in unclassified drug, traditional medicine, cancer, in vivo study—antidiabetic activity, and animals—anti-inflammatory activity. In summary, it has been observed that the trend in global research is focused more on the search for new medicines or active compounds rather than on the cultivation or domestication of plant species with this demonstrated potential.

Artemisia afra, a controversial herbal remedy or a treasure trove of new drugs?

ETHNOPARMACOLOGICAL RELEVANCE

Artemisia afra is one of the most widely used herbal remedies in South Africa. This highly aromatic shrub is used to treat various disorders including coughs, colds, influenza, and malaria. Due to the long tradition of use and popularity of A. afra, it has been successfully commercialised and can currently be bought from various internet stores and pharmacies. The most notable indication is for the prophylaxis and treatment of Plasmodium falciparum infections. In 2013, the Medicine Control Council (MCC) of South Africa banned the sale of A. afra for the treatment of malaria because it lacks scientific evidence of efficacy. This resulted in a lawsuit being filed in 2017 against the MCC by an herbal company which claimed that artemisinin was responsible for A. afra's antiplasmodial activity. At the time, no scientific literature reported that A. afra contained artemisinin.

MATERIALS AND METHODS

This review aims to collate all available scientific literature regarding the phytochemistry and biological activity, focusing on antimalarial activity, of A. afra published from 2009 to 2019 and follows on our earlier review, which covered all literature until 2009. All scientific literature in English published between 2009 and June 2019 were retrieved from scientific databases (Scifinder scholar, Web of Science, Scopus, PubMed, Google scholar) and a number of books regarding medicinal plants in South Africa were also consulted.

RESULTS

In the last decade very few compounds have been identified in A. afra, none of which were novel compounds. Based on all the tests that have been conducted using extracts and compounds of A. afra in a disparate variety of in vitro and in vivo bioassays, the results indicate only weak biological activity. The activity of extracts, and in some cases pure compounds, exhibited IC₅₀ or MIC values of 1000-10 000 fold less active than the positive controls. In contrast, and quite surprisingly, two randomised controlled trials were recently conducted (Schistosoma mansoni and Plasmodium falciparum infected patients) and although criticised based on design, execution, statistical analysis and ethical concerns, showed remarkably positive results.

CONCLUSIONS

Pre-clinical in vitro and in vivo animal experiments failed to yield any promising drug leads. However, if the recent randomised controlled trials can be independently replicated in well-designed and executed clinical trials it might indicate that A. afra contain powerful 'prodrugs'. Future research on A. afra should therefore focus on reproducing the randomised controlled trials and on artificially metabolising A. afra extracts/compounds in order to identify the presence of any 'prodrugs'.

The potential of plant systems to break the HIV-TB link

Tuberculosis (TB) and human immunodeficiency virus (HIV) can place a major burden on healthcare systems and constitute the main challenges of diagnostic and therapeutic programmes. Infection with HIV is the most common cause of Mycobacterium tuberculosis (Mtb), which can accelerate the risk of latent TB reactivation by 20-fold. Similarly, TB is considered the most relevant factor predisposing individuals to HIV infection. Thus, both pathogens can augment one another in a synergetic manner, accelerating the failure of immunological functions and resulting in subsequent death in the absence of treatment. Synergistic approaches involving the treatment of HIV as a tool to combat TB and vice versa are thus required in regions with a high burden of HIV and TB infection. In this context, plant systems are considered a promising approach for combatting HIV and TB in a resource-limited setting because plant-made drugs can be produced efficiently and inexpensively in developing countries and could be shared by the available agricultural infrastructure without the expensive requirement needed for cold chain storage and transportation. Moreover, the use of natural products from medicinal plants can eliminate the concerns associated with antiretroviral therapy (ART) and anti-TB therapy (ATT), including drug interactions, drug-related toxicity and multidrug resistance. In this review, we highlight the potential of plant system as a promising approach for the production of relevant pharmaceuticals for HIV and TB treatment. However, in the cases of HIV and TB, none of the plant-made pharmaceuticals have been approved for clinical use. Limitations in reaching these goals are discussed.

Herbal remedies used for the treatment of infertility in males and females by traditional healers in the rural areas of the West Bank/Palestine

Background

Infertility is considered one of the global public health problems and during human history, it is also considered one of the unsolved problems of the continuous human race. This study aimed to collect and document the ethnopharmacological data on herbal remedies, which traditionally used by Palestinian healers in the rural areas of the West Bank area for the treatment of infertility in males and females.

Methods

Using a semi-structured questionnaire, an ethnopharmacological survey of medicinal plants used for the treatment of infertility in the West Bank area of Palestine was investigated. This survey involved 51 traditional healers which were interviewed in rural areas from 9 Palestinian regions.

Results

Information about 31 plants used in the treatment of infertility in females and 24 plants used in the treatment of infertility in males were collected. This information including names of plants, parts used, mode and methods of preparation which were obtained from 51 traditional healers interviewed in rural areas of 9 regions of the West Bank/Palestine. This investigation is the first scientific work in the Middle East area which collected information about herbal remedies used by local Palestinian traditional healers for the treatments of infertility in males and females. The highest Frequency of Citation (FC) of herbal remedies used in case of infertility in females, were 98.04% for pollen grains from Ceratonia siliqua, 88.24% for Anastatica hierochuntica fruits and 84.31% for Parietaria judaica leaves, while the highest Frequency of Citation (FC) of herbal remedies used in case of infertility in males were 96.08% for Ferula hermonis roots, 88.24% for Phlomis brachyodon leaves and 86.27% for Phoenix dactylifera pollen grains.

Conclusion

Herbal healers in the West Bank area of Palestine have a wide range of herbal remedies used in case of infertility in males and in females. Unfortunately, most of them lack scientific evidence of pharmacological or toxicological nature. Therefore, the information obtained in this study can serve as a scientific base for further investigations to determine their efficacy and safety which might contribute to better integration of Palestinian traditional medicine into the global health system in the future.

Impact of Efavirenz Metabolism on Loss to Care in Older HIV+ Africans

BACKGROUND AND OBJECTIVE: Efavirenz is commonly used in Africa and is frequently associated with neurocognitive toxicity, which may compromise clinical outcomes. Older individuals are at increased risk for drug toxicity and clinical outcomes may be worse in older age, particularly among those individuals with cytochrome P450 (CYP) 2B6 polymorphisms associated with slower efavirenz metabolism. The aim of this study was to determine if the CYP2B6 polymorphisms differentially impacts loss to care in older people.

METHODS

We conducted a prospective cohort study of 914 treatment-naïve HIV+ adults initiating efavirenz-based antiretroviral treatment at public HIV clinics in Gaborone, Botswana between 2009 and 2013. Older age, defined as age ≥ 50 years, was the primary exposure and loss to care at 6 months was the primary outcome. Interaction between age and CYP2B6 516G>T and 983T>C polymorphisms, defined as extensive, intermediate, and slow metabolism, was assessed. Neurocognitive toxicity was measured using a symptom questionnaire. Age-stratified logistic regression was performed to identify factors associated with loss to care.

RESULTS

Older age was associated with loss to care (OR 1.95, 95% CI 1.30-2.92). Age modified the effect of CYP2B6 genotype on loss to care with older, slow metabolizers at over four-fold higher risk when compared to older, intermediate metabolizers (OR 4.06 95% CI 1.38-11.89); neurocognitive toxicity did not mediate this risk. CYP2B6 metabolism genotype did not increase risk of loss to care in younger participants.

CONCLUSION

Older age was associated with loss to care, especially among those with slow efavirenz metabolism. Understanding the relationship between older age and CYP2B6 genotype will be important to improving outcomes in an aging population initiating efavirenz-based ART in similar settings.

Antioxidant and Antimelanogenic Activities of Compounds Isolated from the Aerial Parts of Achillea alpina L

Achillea alpina is widely distributed in Korea and is often used as a folk medicine for stomach disorders. Although a previous study isolated antioxidant compounds (flavonoid O-glucoside, sesquiterpene) from this plant, no systematic study of its chemical constituents had been reported. The present study aimed to identify the phytochemicals present in a methanol extract of A. alpina, assess their potential antioxidant activities in vitro, and determine their effects on melanogenesis in B16F10 melanoma cells. Column chromatographic separation of aqueous fractions of A. alpina led to the isolation of 17 compounds. The chemical structures of these compounds were determined using spectroscopic data from electrospray ionization-mass spectrometry and nuclear magnetic resonance. To the best of our knowledge, the present study is the first to identify compounds 2-10 and 12-17 in A. alpina. Furthermore, compound 6 possessed powerful antioxidant activity, while compound 15 suppressed intracellular tyrosinase activity and thus reduced melanogenesis in B16F10 cells. Therefore, our research suggested that these naturally occurring compounds have the potential to reduce oxidative stress and promote skin whitening. Further investigations will be required to elucidate the mechanisms underlying the antioxidant and antityrosinase activities of these compounds.

Safety effect of fractions from methanolic leaf extract of Ocimum gratissimum on reproduction in male wistar rats

This study evaluates the reproductive toxicity of ethyl acetate and butanolic fractions from crude methanolic leaf extract of Ocimum gratissimum in male Wistar rats. Acute toxicity was assessed to determine the safety dose, Sub-chronic reproductive toxicity studies were carried out by administering daily 25, 100 and 400 mg/kg body weight doses of the fractions to respective group of animals and 1 ml of normal saline daily for the control group for 28 days. Blood, epididymis and testes were harvested for reproductive hormones, sperm parameters, and histopathologic analysis respectively. There was significant (P < 0.05) increase in serum levels of testosterone, body-weight gain, sperm count. There was also apparent increase in mean-testicular weight and preservation of testicular histology with increase spermatogenesis in both the ethyl acetate and butanolic fraction treated groups compared with control. Serum levels of luteinising hormone was however significantly (P < 0.05) decrease across the groups compared to control. These effects were more pronounced in the butanolic fraction group compared to the ethyl acetate treated group. Sperm motility was also significantly (P < 0.05) higher in the ethyl acetate treated group compared to control. Findings from this studies demonstrate that these fractions were non-toxic at the tested doses with regards to male reproduction but, rather, exhibited fertility enhancing effects which was better with the butanolic fraction. Our findings also shows that the ethyl acetate fraction may be safer than the butanolic fraction.

Widespread use of herbal medicines by people living with human immunodeficiency virus and contamination of herbal medicines with antiretrovirals in Nigeria

Herbal medication use amongst people living with human immunodeficiency virus (PLWH) is widespread and understudied. This study aimed to evaluate the prevalence of herbal medicine use amongst PLWH and possible contamination with antiretrovirals (ARVs). Countrywide collection of herbal samples sold by street vendors in Nigeria for the following indications: human immunodeficiency virus (HIV), acquired immune deficiency syndrome, fever and general weakness. Samples were screened using a validated liquid chromatography-mass spectrometry/mass spectrometry method for the presence of the following ARVs: efavirenz, nevirapine, lopinavir, darunavir, ritonavir, atazanavir, emtricitabine, tenofovir and lamivudine. A survey was conducted among 742 PLWH attending four HIV clinics in Nigeria. Data were collected using a structured questionnaire and analysed using IBM SPSS statistics version 22.0 (IBM Corp., 2013, Armond, NY). Of the 138 herbal medicines sampled, three (2%) contained detectable levels of tenofovir, emtricitabine and/or lamivudine. Additionally, of the 742 PLWH surveyed, 310 (41.8%) reported herbal medicine use. Among the users, 191 (61.6%) started taking herbals after commencing HIV therapy while herbal medicine use preceded ARVs treatment in 119 (38.4%) PLWH. We found herbal use to be widespread among PLWH in Nigeria, with increasing use after commencing ARV. Three herbal preparations were also found to contain detectable levels of ARVs. This is a concern and should be studied widely across the region and countries where herbal medicine use is prevalent and poorly regulated.

Integration of botanicals in contemporary medicine: road blocks, checkpoints and go-ahead signals

The use of botanicals for maintaining good health and preventing diseases is undisputed. The claimed health benefits of natural health products and herbal medicines are based on traditional claims, positive results obtained in preclinical studies and early phase clinical trials that are not backed by safety and efficacy evidences approved by regulatory agencies. Although, the popularity of botanicals is growing, health care practitioners of modern medicine seldom recommend their use because of ill equipped database of their safety and potency. This review discusses problems that preclude botanicals from integrating into the mainstream contemporary therapeutics and cues that provide impetus for their realisation.

Natural Products for Drug Discovery in the 21st Century: Innovations for Novel Drug Discovery

The therapeutic properties of plants have been recognised since time immemorial. Many pathological conditions have been treated using plant-derived medicines. These medicines are used as concoctions or concentrated plant extracts without isolation of active compounds. Modern medicine however, requires the isolation and purification of one or two active compounds. There are however a lot of global health challenges with diseases such as cancer, degenerative diseases, HIV/AIDS and diabetes, of which modern medicine is struggling to provide cures. Many times the isolation of "active compound" has made the compound ineffective. Drug discovery is a multidimensional problem requiring several parameters of both natural and synthetic compounds such as safety, pharmacokinetics and efficacy to be evaluated during drug candidate selection. The advent of latest technologies that enhance drug design hypotheses such as Artificial Intelligence, the use of 'organ-on chip' and microfluidics technologies, means that automation has become part of drug discovery. This has resulted in increased speed in drug discovery and evaluation of the safety, pharmacokinetics and efficacy of candidate compounds whilst allowing novel ways of drug design and synthesis based on natural compounds. Recent advances in analytical and computational techniques have opened new avenues to process complex natural products and to use their structures to derive new and innovative drugs. Indeed, we are in the era of computational molecular design, as applied to natural products. Predictive computational softwares have contributed to the discovery of molecular targets of natural products and their derivatives. In future the use of quantum computing, computational softwares and databases in modelling molecular interactions and predicting features and parameters needed for drug development, such as pharmacokinetic and pharmacodynamics, will result in few false positive leads in drug development. This review discusses plant-based natural product drug discovery and how innovative technologies play a role in next-generation drug discovery.

Clinical Application of Epilepsy Genetics in Africa: Is Now the Time?

Over 80% of people with epilepsy live in low- to middle-income countries where epilepsy is often undiagnosed and untreated due to limited resources and poor infrastructure. In Africa, the burden of epilepsy is exacerbated by increased risk factors such as central nervous system infections, perinatal insults, and traumatic brain injury. Despite the high incidence of these etiologies, the cause of epilepsy in over 60% of African children is unknown, suggesting a possible genetic origin. Large-scale genetic and genomic research in Europe and North America has revealed new genes and variants underlying disease in a range of epilepsy phenotypes. The relevance of this knowledge to patient care is especially evident among infants with early-onset epilepsies, where early genetic testing can confirm the diagnosis and direct treatment, potentially improving prognosis and quality of life. In Africa, however, genetic epilepsies are among the most under-investigated neurological disorders, and little knowledge currently exists on the genetics of epilepsy among African patients. The increased diversity on the continent may yield unique, important epilepsy-associated genotypes, currently absent from the North American or European diagnostic testing protocols. In this review, we propose that there is strong justification for developing the capacity to offer genetic testing for children with epilepsy in Africa, informed mostly by the existing counseling and interventional needs. Initial simple protocols involving well-recognized epilepsy genes will not only help patients but will give rise to further clinically relevant research, thus increasing knowledge and capacity.

Ten Years' Experience with the CYP2D6 Activity Score: A Perspective on Future Investigations to Improve Clinical Predictions for Precision Therapeutics

The seminal paper on the CYP2D6 Activity Score (AS) was first published ten years ago and, since its introduction in 2008, it has been widely accepted in the field of pharmacogenetics. This scoring system facilitates the translation of highly complex CYP2D6 diplotype data into a patient’s phenotype to guide drug therapy and is at the core of all CYP2D6 gene/drug pair guidelines issued by the Clinical Pharmacogenetics Implementation Consortium (CPIC). The AS, however, only explains a portion of the variability observed among individuals and ethnicities. In this review, we provide an overview of sources in addition to CYP2D6 genotype that contribute to the variability in CYP2D6-mediated drug metabolism and discuss other factors, genetic and non-genetic, that likely contribute to the observed variability in CYP2D6 enzymatic activity.

Pharmacokinetics of Sulfadoxine and Pyrimethamine for Intermittent Preventive Treatment of Malaria During Pregnancy and After Delivery

Sulfadoxine/pyrimethamine is recommended for intermittent preventative treatment of malaria during pregnancy. Data from 98 women during pregnancy and 77 after delivery in four African countries were analyzed using nonlinear mixed‐effects modeling to characterize the effects of pregnancy, postpartum duration, and other covariates such as body weight and hematocrit on sulfadoxine/pyrimethamine pharmacokinetic properties. During pregnancy, clearance increased 3‐fold for sulfadoxine but decreased by 18% for pyrimethamine. Postpartum sulfadoxine clearance decreased gradually over 13 weeks. This finding, together with hematocrit‐based scaling of plasma to whole‐blood concentrations and allometric scaling of pharmacokinetics parameters with body weight, enabled site‐specific differences in the pharmacokinetic profiles to be reduced significantly but not eliminated. Further research is necessary to explain residual site‐specific differences and elucidate whether dose‐optimization, to address the 3‐fold increase in clearance of sulfadoxine in pregnant women, is necessary, viable, and safe with the current fixed dose combination of sulfadoxine/pyrimethamine.

Building Capability for Clinical Pharmacology Research in Sub-Saharan Africa

A strong scientific rationale exists for conducting clinical pharmacology studies in target populations because local factors such as genetics, environment, comorbidities, and diet can affect variability in drug responses. However, clinical pharmacology studies are not widely conducted in sub-Saharan Africa, in part due to limitations in technical expertise and infrastructure. Since 2012, a novel public-private partnership model involving research institutions and a pharmaceutical company has been applied to developing increased capability for clinical pharmacology research in multiple African countries.

Diospyros, an under-utilized, multi-purpose plant genus: A review

The genus Diospyros from family Ebenaceae has versatile uses including edible fruits, valuable timber, and ornamental uses. The plant parts of numerous species have been in use as remedies in various folk healing practices, which include therapy for hemorrhage, incontinence, insomnia, hiccough, diarrhea etc. Phytochemical constituents such as terpenoids, ursanes, lupanes, polyphenols, tannins, hydrocarbons, and lipids, benzopyrones, naphthoquinones, oleananes, and taraxeranes have been isolated from different species of this genus. The biological activities of these plants such as antioxidant, anti-inflammatory, analgesic, antipyretic, anti-diabetic, antibacterial, anthelmintic, antihypertensive, cosmeceutical, enzyme-inhibitory etc. have been validated by means of an in vitro, in vivo, and clinical tests. As a rich reserve of pharmacologically important components, this genus can accelerate the pace of drug discovery. Accordingly, the aim of the present review is to survey and summarize the recent literature pertaining to the medicinal and pharmacological uses of Diospyros, and to select experimental evidence on the pharmacological properties of this genus. In addition, the review also aims at identifying areas that need development to make use of this genus, especially its fruit and phytochemicals as means for economic development and for drug discovery.

Pharmacokinetic, Pharmacogenetic, and Other Factors Influencing CNS Penetration of Antiretrovirals

Neurological complications associated with the human immunodeficiency virus (HIV) are a matter of great concern. While antiretroviral (ARV) drugs are the cornerstone of HIV treatment and typically produce neurological benefit, some ARV drugs have limited CNS penetration while others have been associated with neurotoxicity. CNS penetration is a function of several factors including sieving role of blood-brain and blood-CSF barriers and activity of innate drug transporters. Other factors are related to pharmacokinetics and pharmacogenetics of the specific ARV agent or mediated by drug interactions, local inflammation, and blood flow. In this review, we provide an overview of the various factors influencing CNS penetration of ARV drugs with an emphasis on those commonly used in sub-Saharan Africa. We also summarize some key associations between ARV drug penetration, CNS efficacy, and neurotoxicity.

African Lettuce (Launaea taraxacifolia) Displays Possible Anticancer Effects and Herb-Drug Interaction Potential by CYP1A2, CYP2C9, and CYP2C19 Inhibition

Medicinal plants are part of the healthcare systems worldwide, especially in low- and middle-income countries. African lettuce (Launaea taraxacifolia) is cultivated extensively in Africa, from Senegal in the west to Ethiopia and Tanzania in the east, and in Southern Africa. Potential anticancer effects of L. taraxacifolia have been suggested, but little is known about putative molecular mechanisms or potential for herb-drug interactions through inhibition or induction of drug-metabolizing enzymes. We investigated the effects of crude aqueous extracts of L. taraxacifolia on growth kinetics and cell cycle progression of the WHC01 esophageal cancer cells. Antiproliferative and apoptotic effects were evaluated using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay and flow cytometry, while examining, in parallel, the genes regulating apoptosis and cell cycle in this cell culture model. In addition, we tested the inhibitory and enzyme kinetic effects of the aqueous L. taraxacifolia using recombinant human CYP450 isozyme model systems (CYP1A2, CYP2C9, and CYP2C19). L. taraxacifolia exhibited a significant growth inhibitory effect on the WHC01 cancer cells. Most cell cycle genes were downregulated. Cell cycle analysis showed a G0-G1 cell cycle arrest in WHC01 cells in the presence of L. taraxacifolia extract, accompanied by morphological changes. L. taraxacifolia extract treatment resulted in downregulation of expression levels of CYP1A2 (p < 0.0005) and CYP2C19 (p < 0.003) by 50-70%. L. taraxacifolia extract caused reversible and time-dependent inhibition of the recombinant CYP1A2, CYP2C9, and CYP2C19. This study provides new insights on possible anticancer effects of L. taraxacifolia, a widely used medicinal plant in parts of Africa and across the world especially by patients with cancer. Further mechanistic studies expanding on these observations would be timely and contribute to the field of global precision medicine that requires solid understanding of drug and herb molecular mechanisms of action and drug-herb interaction potentials, given the worldwide use of medicinal plants.

Medicinal plants used by traditional healers from South-West Algeria: An ethnobotanical study

Background/Aim:

This study aimed to document and analyzes the local knowledge of medicinal plants’ use by traditional healers in South-west Algeria.

Methods:

The ethnobotanical survey was conducted in two Saharian regions of South-west of Algeria: Adrar and Bechar. In total, 22 local traditional healers were interviewed using semi-structured questionnaire and open questions. Use value (UV), fidelity level (FL), and informant consensus factor (FIC) were used to analyze the obtained data.

Results:

Our results showed that 83 medicinal plants species belonging to 38 families are used by traditional healers from South-west of Algeria to treat several ailments. Lamiaceae, Asteraceae, Apiaceae, and Fabaceae were the most dominant families with 13, 8, 6, and 4 species, respectively. Leaves were the plant parts mostly used (36%), followed by seeds (18%), aerial parts (17%) and roots (12%). Furthermore, a decoction was the major mode of preparation (49%), and oral administration was the most preferred (80%). Thymus vulgaris L. (UV = 1.045), Zingiber officinale Roscoe (UV = 0.863), Trigonella foenum-graecum L. (UV=0.590), Rosmarinus officinalis L. (UV = 0.545), and Ruta chalepensis L. (UV = 0.5) were the most frequently species used by local healers. A great informant consensus has been demonstrated for kidney (0.727), cancer (0.687), digestive (0.603), and respiratory diseases.

Conclusion:

This study revealed rich ethnomedicinal knowledge in South-west Algeria. The reported species with high UV, FL, and FIC could be of great interest for further pharmacological studies.

In Vitro Reversible and Time-Dependent CYP450 Inhibition Profiles of Medicinal Herbal Plant Extracts Newbouldia laevis and Cassia abbreviata: Implications for Herb-Drug Interactions

This study evaluated the effects of Newbouldia laevis and Cassia abbreviata extracts on CYP450 enzyme activity. Recombinant CYP450 enzyme and fluorogenic substrates were used for evaluating inhibition, allowing the assessment of herb–drug interactions (HDI). Phytochemical fingerprinting was performed using UPLC-MS. The herbal extracts were risk ranked for HDI based on the IC₅₀ values determined for each CYP enzyme. Newbouldia laevis inhibited CYP1A2, CYP2C9, and CYP2C19 enzyme activities with K_i of 2.84 µg/mL, 1.55 µg/mL, and 1.23 µg/mL, respectively. N. laevis exhibited a TDI (4.17) effect on CYP1A2 but not CYP2C9 and CYP2C19 enzyme activities. Cassia abbreviata inhibited CYP1A2, CYP2C9, and CYP2C19 enzyme activities showing a K_i of 4.86 µg/mL, 5.98 µg/mL, and 1.58 µg/mL, respectively. TDI potency assessment for Cassia abbreviata showed it as a potential TDI candidate (1.64) for CYP1A2 and CYP2C19 (1.72). UPLC-MS analysis showed that Newbouldia laevis and Cassia abbreviata possess polyphenols that likely give them their therapeutic properties; some of them are likely to be responsible for the observed inhibition. The observations made in this study suggest the potential for these herbal compounds to interact, especially when co-administered with other medications metabolized by these CYP450 enzymes.

Is there a role of pharmacogenomics in Africa

Pharmacogenomics has the potential of transforming clinical research and improving healthcare in sub-Saharan Africa (SSA). The role of African genome diversity and the opportunities for pharmacogenomics research are highlighted and will enable discovery of novel genetic mechanisms and validation of established markers. African genomics and biobank consortia will play an important role in building capacity for pharmacogenomics in SSA.

Inhibition of CYP2B6 by Medicinal Plant Extracts: Implication for Use of Efavirenz and Nevirapine-Based Highly Active Anti-Retroviral Therapy (HAART) in Resource-Limited Settings

Highly active antiretroviral therapy (HAART) has greatly improved health parameters of HIV infected individuals. However, there are several challenges associated with the chronic nature of HAART administration. For populations in health transition, dual use of medicinal plant extracts and conventional medicine poses a significant challenge. There is need to evaluate interactions between commonly used medicinal plant extracts and antiretroviral drugs used against HIV/AIDS. Efavirenz (EFV) and nevirapine (NVP) are the major components of HAART both metabolized by CYP2B6, an enzyme that can potentially be inhibited or induced by compounds found in medicinal plant extracts. The purpose of this study was to evaluate the effects of extracts of selected commonly used medicinal plants on CYP2B6 enzyme activity. Recombinant human CYP2B6 was used to evaluate inhibition, allowing the assessment of herb-drug interactions (HDI) of medicinal plants Hyptis suaveolens, Myrothamnus flabellifolius, Launaea taraxacifolia, Boerhavia diffusa and Newbouldia laevis. The potential of these medicinal extracts to cause HDI was ranked accordingly for reversible inhibition and also classified as potential time-dependent inhibitor (TDI) candidates. The most potent inhibitor for CYP2B6 was Hyptis suaveolens extract (IC₅₀ = 19.09 ± 1.16 µg/mL), followed by Myrothamnus flabellifolius extract (IC₅₀ = 23.66 ± 4.86 µg/mL), Launaea taraxacifolia extract (IC₅₀ = 33.87 ± 1.54 µg/mL), and Boerhavia diffusa extract (IC₅₀ = 34.93 ± 1.06 µg/mL). Newbouldia laevis extract, however, exhibited weak inhibitory effects (IC₅₀ = 100 ± 8.71 µg/mL) on CYP2B6. Launaea taraxacifolia exhibited a TDI (3.17) effect on CYP2B6 and showed a high concentration of known CYP450 inhibitory phenolic compounds, chlorogenic acid and caffeic acid. The implication for these observations is that drugs that are metabolized by CYP2B6 when co-administered with these herbal medicines and when adequate amounts of the extracts reach the liver, there is a high likelihood of standard doses affecting drug plasma concentrations which could lead to toxicity.