The antiplasmodial activity of isolates from Ajuga remota

Nephroprotective Effect of the Leaf Extract of Ajuga remota Benth Against Gentamicin-Induced Nephrotoxicity in Swiss Albino Mice

Background

Drug-induced kidney injury was among the most common renal damages, from which gentamicin occupies around 25% of this injury. Gentamicin-induced renal damage is caused by increased free radicals with subsequent amplified inflammation. Ajuga remota leaf extract has many phytochemicals with antioxidant activities, which may improve gentamicin-induced renal damage. Thus, we aimed to investigate the nephroprotective effect of Ajuga remota leaf methanolic extract on gentamicin-induced nephrotoxicity in Swiss Albino Mice.

Methods

An experimental study design was used on 30 experimental mice randomly allocated in six groups: Group I, II, II, IV, and VI, among which mice were given only distilled water, only gentamicin, 600 mg/kg Ajuga remota leaf extract only, gentamicin along with 200 mg/kg extract, gentamicin with 400 mg/kg extract and gentamicin with 600 mg/kg extract, respectively. At the end of the experiment, the mice were sacrificed after being anaesthetized, and blood samples were collected through a cardiac puncture for renal function tests while the kidneys were removed for histopathological evaluation. The data were entered into Epidata version 4.6 and exported to SPSS version 25 for further analysis using one-way analysis of variance. Statistical significance was set at p < 0.05.

Results

Group II mice had significantly higher levels of serum creatinine and blood urea levels compared to group I and III. The body weight of the mice in group V and group VI showed a significant increase compared with Group II. Serum creatinine and blood urea levels were reduced significantly in the Ajuga remota leaf extract administered group of mice compared to group II. Abnormal kidney architectural changes were seen among group II mice; however, those changes were improved after administration of Ajuga remota leaf methanolic extract.

Conclusion

Methanol extract of Ajuga remota leaf provided effective protection against gentamicin-induced oxidative renal damage through its antioxidant effects.

In vitro and in vivo antimalarial activity of green synthesized silver nanoparticles using Sargassum tenerrimum - a marine seaweed

Green nanotechnology has recently attracted a lot of attention as a potential technique for drug development. In the present study, silver nanoparticles were synthesised by using Sargassum tenerrimum, a marine seaweed crude extract (Ag-ST), and evaluated for antimalarial activity in both in vitro and in vivo models. The results showed that Ag-ST nanoparticles exhibited good antiplasmodial activity with IC50 values 7.71±0.39 µg/ml and 23.93±2.27 µg/ml against P. falciparum and P. berghei respectively. These nanoparticles also showed less haemolysis activity suggesting their possible use in therapeutics. Further, P. berghei infected C57BL/6 mice were used for the four-day suppressive, curative and prophylactic assays where it was noticed that the Ag-ST nanoparticles significantly reduced the parasitaemia and there were no toxic effects observed in the biochemical and haematological parameters. Further to understand its possible toxic effects, both in vitro and in vivo genotoxicological studies were performed which revealed that these nanoparticles are non-genotoxic in nature. The possible antimalarial activity of Ag-ST may be due to the presence of bioactive phytochemicals and silver ions. Moreover, the phytochemicals prevent the nonspecific release of ions responsible for low genotoxicity. Together, the bio-efficacy and toxicology outcomes demonstrated that the green synthesized silver nanoparticles (Ag-ST) could be a cutting-edge alternative for therapeutic applications.

Anti-Convulsant Activity of Soxhlet Leaf Extracts of Ajuga Integrifolia Buch.-Ham. Ex D.Don (Lamiaceae) in Mice

Background

The leaves of Ajuga integrifolia Buch.-Ham. ex D.Don (Lamiaceae) have long been used as an anti-convulsant remedy in Ethiopian traditional medicine. However, the evidence supporting their use is sparse in the literature. This study was conducted to add to the existing body of knowledge about the anti-convulsant activity of the plant.

Methods

The anti-convulsant activity of the extract was investigated in both acute (pentylenetetrazol [PTZ], 80 mg/kg; and maximal electroshock [MES]) and chronic (PTZ, 35 mg/kg) kindling seizure models. For the experimental paradigms, various doses of the extract (100, 200, and 400 mg/kg) were administered. Positive controls received sodium valproate (200 mg/kg) for the PTZ model and phenytoin (25 mg/kg) for the MES model. Parameters including the onset of clonus and duration of hindlimb tonic extension were recorded and compared with controls. Moreover, the total alkaloid, flavonoid, and phenol contents of the extracts were determined.

Results

Ethyl acetate extract produced a superior effect among all solvent extracts in both the PTZ and MES models. At all doses, it significantly delayed the mean onset of clonus (p<0.01) in the PTZ test compared to controls. It also significantly reduced (p<0.001) the mean duration of hindlimb tonic extension in the MES model. Treatment of mice with 200 mg/kg (p<0.01) and 400 mg/kg (p<0.001) of ethyl acetate extract significantly protected against PTZ-induced kindling compared to controls. The leaf was found to contain 10.002±0.119 mg atropine equivalent per gram of dry extract of alkaloids, 9.045±0.8445 mg quercetin equivalent per gram of dry extract of flavonoids, and 21.928±1.118 mg gallic acid equivalent per gram of dry extract of phenols.

Conclusion

This study indicated that the plant A. integrifolia has anti-convulsant activity in both acute and chronic models of seizure. This plant represents a potential source for the development of a new anti-epileptic drug for pharmacoresistant epilepsy.

Medicinal Plant Extracts Evaluated In Vitro and In Vivo for Antidiabetic Activities in Ethiopia: Bases for Future Clinical Trials and Related Investigations

Background

Diabetes mellitus (DM) is a metabolic disorder characterized by a persistent rise in the blood glucose level resulting from defects in cellular insulin function, secretion, or both, which affects millions of people every year. Several drawbacks have been stated with the use of marketed antidiabetic medicines such as drug resistance, adverse effects, toxicities, and even costs. Due to these several limitations, searching for novel antidiabetic medicines from medicinal plants (MPs) is becoming an active area of research. Therefore, MPs are exemplary sources of medicines with many accessible agents being obtained from them because numerous active constituents are isolated from them for direct use as pharmacological medicines or act as lead compounds. This paper was aimed to synthesize a concluding remark using in vitro and in vivo evaluations of extracts and fractions for antidiabetic potentials in Ethiopia, which can be used to direct future clinical trials and related investigations.

Method

So as to get data on the different investigations, publications related to experimental evaluations on animal diabetic models in Ethiopia were searched from databases, such as Google Scholar, Web of Science, Medline, PubMed, and Scopus using English key terms.

Results

In this paper, about 37 research findings based on data from various areas of Ethiopia published until the end of November 2020 were included. A total of 37 MP species extracts and fractions belonging to 19 families have been revealed in vitro or in vivo for potential antidiabetic activities. Crude extracts were carried out mostly by hydromethanolic whereas fractions were done mostly by chloroform. Leaves were the most commonly experimentally investigated plant part. Among the MP species experimentally studied, the most frequently used to treat DM in Ethiopia were Thymus schimperi Ronniger (Lamiaceae), Moringa stenopetala (Baker f.; Moringaceae), Ajuga remota Benth (Lamiaceae), and Datura stramonium Linn. (Solanaceae).

Conclusion

This paper gives aggregate evidences on the potential antidiabetic activities of MPs in Ethiopia. Antidiabetic MPs used in Ethiopia represent crucial input for the future development of novel antidiabetic drugs. To this end, more pharmacological and toxicological investigations need to be considered to prove the safety of constituents obtained from these MPs. Finally, we recommend upcoming research to ensure future success in the clinical study and development of novel medicines for DM treatment from these frequently evaluated MPs.

Antiplasmodial, antimalarial activities and toxicity of African medicinal plants: a systematic review of literature

BACKGROUND

Malaria still constitutes a major public health menace, especially in tropical and subtropical countries. Close to half a million people mainly children in Africa, die every year from the disease. With the rising resistance to frontline drugs (artemisinin-based combinations), there is a need to accelerate the discovery and development of newer anti-malarial drugs. A systematic review was conducted to identify the African medicinal plants with significant antiplasmodial and/or anti-malarial activity, toxicity, as wells as assessing the variation in their activity between study designs (in vitro and in vivo).

METHODS

Key health-related databases including Google Scholar, PubMed, PubMed Central, and Science Direct were searched for relevant literature on the antiplasmodial and anti-malarial activities of African medicinal plants.

RESULTS

In total, 200 research articles were identified, a majority of which were studies conducted in Nigeria. The selected research articles constituted 722 independent experiments evaluating 502 plant species. Of the 722 studies, 81.9%, 12.4%, and 5.5% were in vitro, in vivo, and combined in vitro and in vivo, respectively. The most frequently investigated plant species were Azadirachta indica, Zanthoxylum chalybeum, Picrilima nitida, and Nauclea latifolia meanwhile Fabaceae, Euphorbiaceae, Annonaceae, Rubiaceae, Rutaceae, Meliaceae, and Lamiaceae were the most frequently investigated plant families. Overall, 248 (34.3%), 241 (33.4%), and 233 (32.3%) of the studies reported very good, good, and moderate activity, respectively. Alchornea cordifolia, Flueggea virosa, Cryptolepis sanguinolenta, Zanthoxylum chalybeum, and Maytenus senegalensis gave consistently very good activity across the different studies. In all, only 31 (4.3%) of studies involved pure compounds and these had significantly (p = 0.044) higher antiplasmodial activity relative to crude extracts. Out of the 198 plant species tested for toxicity, 52 (26.3%) demonstrated some degree of toxicity, with toxicity most frequently reported with Azadirachta indica and Vernonia amygdalina. These species were equally the most frequently inactive plants reported. The leaves were the most frequently reported toxic part of plants used. Furthermore, toxicity was observed to decrease with increasing antiplasmodial activity.

CONCLUSIONS

Although there are many indigenous plants with considerable antiplasmodial and anti-malarial activity, the progress in the development of new anti-malarial drugs from African medicinal plants is still slothful, with only one clinical trial with Cochlospermum planchonii (Bixaceae) conducted to date. There is, therefore, the need to scale up anti-malarial drug discovery in the African region.

Diterpenoids from the Whole Plants of Ajuga nipponensis and Their Inhibition of RANKL-Induced Osteoclastogenesis

Two new diterpenoids, ajudecunoid A (1) and ajudecunoid B (14), along with thirteen known diterpenoids, were isolated from the whole plants of Ajuga nipponensis Makino. Their structures were elucidated by the extensive spectroscopic analysis (UV, IR, MS, and NMR). The absolute configurations of ajudecunoid A (1) and ajudecunoid B (14) were defined through analysis of X-ray crystallography. Fifteen compounds were evaluated for inhibition of the formation of osteoclasts in bone marrow-derived macrophages (BMM) cells. Two neo-clerodane diterpenoids ajuganipponin B (5) and (12S)-6α,19-diacetoxy-18-chloro-4α-hydroxy-12-tigloyloxy-neo-clerod-13-en-15,16-olide (12) showed significant inhibition of osteoclastogenesis with IC₅₀ values of 0.88 and 0.79 μM, respectively. Here we firstly reported diterpenoids with anti-osteoclastogenesis activity from A. nipponensis.

In Depth Natural Product Discovery from the Basidiomycetes Stereum Species

Natural metabolites from microorganisms play significant roles in the discovery of drugs, both for disease treatments in humans, and applications in agriculture. The Basidiomycetes Stereum genus has been a source of such bioactive compounds. Here we report on the structures and activities of secondary metabolites from Stereum. Their structural types include sesquiterpenoids, polyketides, vibralactones, triterpenoids, sterols, carboxylic acids and saccharides. Most of them showed biological activities including cytotoxic, antibacterial, antifungal, antiviral, radical scavenging activity, autophagy inducing activity, inhibiting pancreatic lipase against malarial parasite, nematocidal and so on. The syntheses of some metabolites have been studied. In this review, 238 secondary metabolites from 10 known species and various unidentified species of Stereum were summarized over the last seven decades.

Antimalarial Plants Used across Kenyan Communities

Malaria is one of the serious health problems in Africa, Asia, and Latin America. Its treatment has been met with chronic failure due to pathogenic resistance to the currently available drugs. This review attempts to compile phytotherapeutical information on antimalarial plants in Kenya based on electronic data. A comprehensive web search was conducted in multidisciplinary databases, and a total of 286 plant species from 75 families, distributed among 192 genera, were retrieved. Globally, about 139 (48.6%) of the species have been investigated for antiplasmodial (18%) or antimalarial activities (97.1%) with promising results. However, there is no record on the antimalarial activity of about 51.4% of the species used although they could be potential sources of antimalarial remedies. Analysis of ethnomedicinal recipes indicated that mainly leaves (27.7%) and roots (19.4%) of shrubs (33.2%), trees (30.1%), and herbs (29.7%) are used for preparation of antimalarial decoctions (70.5%) and infusions (5.4%) in Kenya. The study highlighted a rich diversity of indigenous antimalarial plants with equally divergent herbal remedy preparation and use pattern. Further research is required to validate the therapeutic potential of antimalarial compounds from the unstudied claimed species. Although some species were investigated for their antimalarial efficacies, their toxicity and safety aspects need to be further investigated.

Systematic review on traditional medicinal plants used for the treatment of malaria in Ethiopia: trends and perspectives

Background

Ethiopia is endowed with abundant medicinal plant resources and traditional medicinal practices. However, available research evidence on indigenous anti-malarial plants is highly fragmented in the country. The present systematic review attempted to explore, synthesize and compile ethno-medicinal research evidence on anti-malarial medicinal plants in Ethiopia.

Methods

A systematic web search analysis and review was conducted on research literature pertaining to medicinal plants used for traditional malaria treatment in Ethiopia. Data were collected from a total of 82 Ethiopian studies meeting specific inclusion criteria including published research articles and unpublished thesis reports. SPSS Version 16 was used to summarize relevant ethno-botanical/medicinal information using descriptive statistics, frequency, percentage, tables, and bar graphs.

Results

A total of 200 different plant species (from 71 families) used for traditional malaria treatment were identified in different parts of Ethiopia. Distribution and usage pattern of anti-malarial plants showed substantial variability across different geographic settings. A higher diversity of anti-malarial plants was reported from western and southwestern parts of the country. Analysis of ethno-medicinal recipes indicated that mainly fresh leaves were used for preparation of remedies. Decoction, concoction and eating/chewing were found to be the most frequently employed herbal remedy preparation methods. Notably, anti-malarial herbal remedies were administered by oral route. Information on potential side effects of anti-malarial herbal preparations was patchy. However, some anti-malarial plants were reported to have potentially serious side effects using different local antidotes and some specific contra-indications.

Conclusion

The study highlighted a rich diversity of indigenous anti-malarial medicinal plants with equally divergent herbal remedy preparation and use pattern in Ethiopia. Baseline information gaps were observed in key geographic settings. Likewise, herbal remedy toxicity risks and countermeasures generally entailed more exhaustive investigation. Experimental research and advanced chemical analysis are also required to validate the therapeutic potential of anti-malarial compounds from promising plant species.

Electronic supplementary material

The online version of this article (doi:10.1186/s12936-017-1953-2) contains supplementary material, which is available to authorized users.

Antidiabetic activity and phytochemical screening of extracts of the leaves of Ajuga remota Benth on alloxan-induced diabetic mice

Background

Ajuga remota Benth is traditionally used in Ethiopia for the management of diabetes mellitus. Since this claim has not been investigated scientifically, the aim of this study was to evaluate the antidiabetic effect and phytochemical screening of the aqueous and 70% ethanol extracts on alloxan-induced diabetic mice.

Methods

After acute toxicity test, the Swiss albino mice were induced with alloxan to get experimental diabetes animals. The fasting mean blood glucose level before and after treatment for two weeks in normal, diabetic untreated and diabetic mice treated with aqueous and 70% ethanol extracts were performed. Data were statistically evaluated by using Statistical Package for the Social Sciences software version 20. P-value <0.05 was considered statistically significant.

Results

The medium lethal doses (LD₅₀) of both extracts were higher than 5000 mg/kg, indicating the extracts are not toxic under the observable condition. Aqueous extracts of A.remota (300 mg/kg and 500 mg/kg body weight) reduced elevated blood glucose levels by 27.83 ± 2.96% and 38.98 ± 0.67% (P < 0.0001), respectively while the 70% ethanol extract caused a reduction of 27.94 ± 1.92% (300 mg/kg) & 28.26 ± 1.82% (500 mg/kg). Treatment with the antidiabetic drug, Glibenclamide (10 mg/kg body weight) lowered blood glucose level by 51.06% (p < 0.05). Phytochemical screening of both extracts indicated the presence of phenolic compounds, flavonoids, saponins, tannins, and steroids, which might contribute to the antidiabetic activity. The extracts, however, did not contain alkaloids and anthraquinones.

Conclusion

The aqueous extract (500 mg/kg) showed the highest percentage reduction in blood glucose levels and the ability of A. remota extracts in reducing blood glucose levels presumably due to the presence of antioxidant constituents such as flavonoids. The effect of the extract supported the traditional claim of the plant.

Chemical and pharmacological research on the plants from genus Ajuga

The genus

In vivo antiplasmodial activity and toxicological assessment of hydroethanolic crude extract of Ajuga remota

BACKGROUND

Malaria is one of the most life-threatening health problems worldwide and treatment has been compromised by drug resistance. Identifying lead molecules from natural products might help to find better anti-malarial drugs, since those obtained from natural sources are still effective against malarial parasites. This study aimed at investigating the in vivo antiplasmodial activity of crude extract of the leaves of Ajuga remota together with its safety in mice models.

METHODS

In vivo parasite growth inhibitory effect of crude extract was assessed in mice inoculated with Plasmodium berghei (ANKA strain). The in vivo antiplasmodial activity of the test extract was performed against early infection (4-day suppressive test), curative effect against established infection and prophylactic effect against residual infection. Acute and sub-acute toxicity were carried out according to OECD guidelines.

RESULTS

In vivo parasite growth inhibition effect of hydroethanolic crude extract of A. remota was evaluated at 30, 50 and 100 mg/kg dose levels. It suppressed parasitaemia by 77.34% at 100 mg/kg dose level in the 4-day test. In curative and prophylactic potential tests, it suppressed parasitaemia by 66.67 and 59.66% at 100 mg/kg dose level, respectively. In vivo toxicity tests revealed no toxicity. All parasitaemia suppressions were statistically significant at P < 0.05 as compared to the vehicle-treated group. The crude extract also prolonged survival time in a dose dependent manner.

CONCLUSIONS

The investigation results suggest that the leave extract of Ajuga remota possesses antimalarial activity.

Diterpenes as lead molecules against neglected tropical diseases

Nowadays, neglected tropical diseases (NTDs) are reported to be present everywhere. Poor and developing areas in the world have received great attention to NTDs. Drug resistance, safety profile, and various challenges stimulate the search for alternative medications. Plant-based drugs are viewed with great interest, as they are believed to be devoid of side effects. Diterpenes, a family of essential oils, have showed attractive biological effects. A systematic review of the literature was carried out to summarize available evidences of diterpenes against NTDs. For this, databases were searched using specific search terms. Among the 2338 collected reports, a total of 181 articles were included in this review. Of them, 148 dealt with investigations using single organisms, and 33 used multiple organisms. No mechanisms of action were reported in the case of 164 reports. A total of 93.92% were related to nonclinical studies, and 4.42% and 1.66% dealt with preclinical and clinical studies, respectively. The review displays that many diterpenes are effective upon Chagas disease, chikungunya, echinococcosis, dengue, leishmaniasis, leprosy, lymphatic filariasis, malaria, schistosomiasis, and tuberculosis. Indeed, diterpenes are amazing drug candidates against NTDs. Copyright © 2016 John Wiley & Sons, Ltd.

Clerodane diterpenes: sources, structures, and biological activities

Covering: 1990 to 2015The clerodane diterpenoids are a widespread class of secondary metabolites and have been found in several hundreds of plant species from various families and in organisms from other taxonomic groups. These substances have attracted interest in recent years due to their notable biological activities, particularly insect antifeedant properties. In addition, the major active clerodanes of Salvia divinorum can be used as novel opioid receptor probes, allowing greater insight into opioid receptor-mediated phenomena, as well as opening additional areas for chemical investigation. This article provides extensive coverage of naturally occurring clerodane diterpenes discovered from 1990 until 2015, and follows up on the 1992 review by Merritt and Ley in this same journal. The distribution, chemotaxonomic significance, chemical structures, and biological activities of clerodane diterpenes are summarized. In the cases where sufficient information is available, structure activity relationship (SAR) correlations and mode of action of active clerodanes have been presented.

Antiplasmodial potential of traditional phytotherapy of some remedies used in treatment of malaria in Meru-Tharaka Nithi County of Kenya

ETHNOPHARMACOLOGICAL RELEVANCE

Medicinal plants play a major role in many communities across the world, in the treatment and prevention of disease and the promotion of general health. The aim of the study was to escalate documentation from an earlier study of medicinal plants, traditionally used to combat malaria by the Ameru community of Imenti Forest area and Gatunga in Eastern Region of Kenya, and validate their ethnopharmacological claims by evaluating their antiplasmodial efficacies.

MATERIALS AND METHODS

The study was carried out in Meru County at Imenti Forest Game Reserve and in Tharaka Nithi County at Gatunga. Traditional health practitioners (THP) were interviewed with a standard questionnaire to obtain information on medicinal plants traditionally used for management of malaria. Group interviews were also held among THPs and members of the community. The antiplasmodial activities of the crude extracts against chloroquine sensitive (D6) and resistant (W2) Plasmodium falciparum were determined using the semi-automated micro-dilution technique that measures the ability of the extracts to inhibit the incorporation of (G-3H) hypoxanthine into the malaria parasite.

RESULTS

Ninety nine (99) species in eighty one (81) genera and forty five (45) families were documented and evaluated for in vitro antiplasmodial activity. Compositae, Fabaceae, Meliceae, Rubiaceae, Rutaceae and Verbenaceae had the highest number of species mentioned in treatment of malaria in Meru/Tharaka Nithi study area. Twenty four (24.2%) species showed antiplasmodial efficacy of IC50 ≤ 5 µg/ml and were considered to have potential for isolation of antimalarial compounds. Eight plant (8) species with moderate antiplasmodial activity namely; Cordia africana, Commiphora africana, Elaeodendron buchananii, Gomphocarpus semilunatus, Tarena graveolens, Plectranthus igniarius, Acacia senegal and Ziziphus abyssinica were documented from this region for the first time for the treatment of malaria. The antiplasmodial activity of MeOH root bark extract of Maytenus obtusifolia was very promising (IC50 < 1.9 µg/ml) and this is the first report on traditional use of M. obtusifolia for treatment of malaria and antimalarial activity.

CONCLUSIONS

The results seem to indicate that ethnopharmacological inquiry used in search for new herbal remedies as predictive and could be used as the basis for search of new active principles. Eight plant (8) species are documented from this region for the first time for the treatment of malaria. This is the first report on traditional use of M. obtusifolia for treatment of malaria and evaluation of its antiplasmodial activity.

Anti-malarial activity and toxicity assessment of Himatanthus articulatus, a plant used to treat malaria in the Brazilian Amazon

Background

Plasmodium falciparum has become resistant to some of the available drugs. Several plant species are used for the treatment of malaria, such as Himatanthus articulatus in parts of Brazil. The present paper reports the phyto-chemistry, the anti-plasmodial and anti-malarial activity, as well as the toxicity of H. articulatus.

Methods

Ethanol and dichloromethane extracts were obtained from the powder of stem barks of H. articulatus and later fractionated and analysed. The anti-plasmodial activity was assessed against a chloroquine resistant strain P. falciparum (W2) in vitro, whilst in vivo anti-malarial activity against Plasmodium berghei (ANKA strain) was tested in mice, evaluating the role of oxidative stress (total antioxidant capacity - TEAC; lipid peroxidation – TBARS, and nitrites and nitrates - NN). In addition, cytotoxicity was evaluated using the HepG2 A16 cell-line. The acute oral and sub-chronic toxicity of the ethanol extract were evaluated in both male and female mice.

Results

Plumieride was isolated from the ethyl acetate fraction of ethanol extract, Only the dichloromethane extract was active against clone W2. Nevertheless, both extracts reduced parasitaemia in P. berghei-infected mice. Besides, a significant reduction in pulmonary and cerebral levels of NN (nitrites and nitrates) was found, as well as in pulmonary TBARS, indicating a reduced oxidative damage to these organs. The ethanol extract showed low cytotoxicity to HepG2 A16 cells in the concentrations used. No significant changes were observed in the in vivo toxicity studies.

Conclusions

The ethanol extract of H. articulatus proved to be promising as anti-malarial medicine and showed low toxicity.

Chemical constituents of Hericium erinaceum associated with the inhibitory activity against cellular senescence in human umbilical vascular endothelial cells

Hericium erinaceum is an edible and medicinal mushroom widely used in Korea, Japan, and China. On the search for biologically active compounds supporting the medicinal usage, the MeOH extract of the fruiting bodies of H. erinaceum was investigated for its chemical constituents. Six compounds were isolated and identified as hericenone D (1), (22E,24R)-5α,8α-epidioxyergosta-6,22-dien-3β-ol (2), erinacerin B (3), hericenone E (4), hericenone F (5) and isohericerin (6) by comparing their spectroscopic data with previously reported values. The inhibitory effects on adriamycin-induced cellular senescence in human dermal fibroblasts (HDFs) and human umbilical vein endothelial cells (HUVECs) of the isolates (1-6) were studied. Among the isolated compounds, ergosterol peroxide (2) reduced senescence associated β-galactosidase (SA-β-gal) activity increased in HUVECs treated with adriamycin. According to experimental data obtained, the active compound may inspire the development of a new pharmacologically useful substance to be used in the treatment and prevention of age-related diseases.

The potential of anti-malarial compounds derived from African medicinal plants, part II: a pharmacological evaluation of non-alkaloids and non-terpenoids

Malaria is currently a public health concern in many countries in the world due to various factors which are not yet under check. Drug discovery projects targeting malaria often resort to natural sources in the search for lead compounds. A survey of the literature has led to a summary of the major findings regarding plant-derived compounds from African flora, which have shown anti-malarial/antiplasmodial activities, tested by in vitro and in vivo assays. Considerations have been given to compounds with activities ranging from "very active" to "weakly active", leading to >500 chemical structures, mainly alkaloids, terpenoids, flavonoids, coumarins, phenolics, polyacetylenes, xanthones, quinones, steroids and lignans. However, only the compounds that showed anti-malarial activity, from "very active" to "moderately active", are discussed in this review.

The potential of anti-malarial compounds derived from African medicinal plants, part I: a pharmacological evaluation of alkaloids and terpenoids

Traditional medicine caters for about 80% of the health care needs of many rural populations around the world, especially in developing countries. In addition, plant-derived compounds have played key roles in drug discovery. Malaria is currently a public health concern in many countries in the world due to factors such as chemotherapy faced by resistance, poor hygienic conditions, poorly managed vector control programmes and no approved vaccines. In this review, an attempt has been made to assess the value of African medicinal plants for drug discovery by discussing the anti-malarial virtue of the derived phytochemicals that have been tested by in vitro and in vivo assays. This survey was focused on pure compounds derived from African flora which have exhibited anti-malarial properties with activities ranging from "very active" to "weakly active". However, only the compounds which showed anti-malarial activities from "very active" to "moderately active" are discussed in this review. The activity of 278 compounds, mainly alkaloids, terpenoids, flavonoids, coumarines, phenolics, polyacetylenes, xanthones, quinones, steroids, and lignans have been discussed. The first part of this review series covers the activity of 171 compounds belonging to the alkaloid and terpenoid classes. Data available in the literature indicated that African flora hold an enormous potential for the development of phytomedicines for malaria.

Micropropagation of Ajuga bracteosa, a medicinal herb

For conservation and genetic transformation, a successful in vitro micropropagation protocol for Ajuga bracteosa, a medicinal herb has been established for the first time. MS medium supplemented with IAA (2 mg/L) and BA (5 mg/L) induced 100 % shoot regeneration with an average of 41.4 shoots of 8.4 cm per culture. Excised in vitro shoots when transferred to MS + IBA (0.5 mg/L) produced 20 roots/shoot of 20.2 cm average length in 100 % cultures. Of the three explants, leaf, petiole and root, leaf displayed quickest response followed by petiole while root was the slowest. Hardening of plantlets was achieved with 82 % survival. The hardened plants were maintained in pots with garden soil under controlled (Temp. 25 ± 2 °C) conditions. RAPD exhibited genetic fidelity with 100 % monomorphism in regenerants.

Ajuga remota Benth.: from ethnopharmacology to phytomedical perspective in the treatment of malaria

Treatment and control of malaria have become more difficult with the spread of drug-resistant parasites and insecticide-resistant mosquito vectors. In the search for new antimalarial drugs, ethnopharmacological sources should merit more attention. Establishing the safety of traditional herbal medicines, along with identifying their active principles, are essential steps in the production of a properly standardized and accessible herbal medicine. Phytochemical characterization could also serve as a base for the development of new chemical compounds. The genus of Ajuga belongs to the family Lamiaceae and contains at least 301 species. Many of these plants have been used in traditional medicine. Ajuga remota in particular is traditionally used as a herbal remedy for fever and infections, and is prescribed for malaria by 66% of the Kenyan herbalists. A large number of compounds have already been isolated from A. remota, including ergosterol-5,8-endoperoxide (6), ajugarin-I (1), 8-O-acetylharpagide (5) and several phytoecdysteroids. In vitro pharmacological studies have been conducted on constituents of A. remota of which some of them displayed a concentration-dependent inhibition of chloroquine-sensitive and -resistant Plasmodium falciparum and Mycobacterium tuberculosis. Inhibition of parasitaemia was demonstrated in mouse models with P. berghei, supporting the traditional use of the plant against malaria. In this state-of-the-art review, A. remota as a possible therapeutic tool for malaria is discussed.

The facilitative effects of bilobalide, a unique constituent of Ginkgo biloba, on synaptic transmission and plasticity in hippocampal subfields

Bilobalide, a unique constituent of Ginkgo biloba, has been reported to potentiate population spikes in hippocampal CA1 pyramidal cells and to protect the brain against cell death. In this study, the effects of bilobalide on synaptic transmission and its plasticity in rat hippocampal subfields were electrophysiologically investigated. Bilobalide (50 μM) significantly potentiated the input-output relationship at Schaffer collateral (SC)-CA1 synapses but not at medial perforant path (MPP)-dentate gyrus (DG), lateral perforant path (LPP)-DG, or mossy fiber (MF)-CA3 synapses. Facilitative effects of bilobalide on synaptic plasticity were only observed at MPP-DG synapses, in which the induction of long-term depression was blocked in the presence of bilobalide. However, no effect on synaptic plasticity was observed at SC-CA1 synapses. These results suggest that bilobalide has differential effects on synaptic efficacy in each hippocampal subfield.

Bioactive neo-clerodane diterpenoids from the whole plants of Ajuga ciliata Bunge

Ten new neo-clerodane diterpenes, ajugaciliatins A-J (1-5, 8-12), along with 17 known analogues (6, 7, 13-27) were isolated from the whole plants of Ajuga ciliata Bunge. Their structures were elucidated by spectroscopic data analysis (IR, ESIMS, HRESIMS, 1D and 2D NMR), and the configuration of 1 was confirmed by X-ray crystallography. All of the compounds were assessed for neuroprotective effects against MPP(+)-induced neuronal cell death in dopaminergic neuroblastoma SH-SY5Y cells. Compounds 2, 6, 7, 9, 10, 15-17, 19, and 20 exhibited moderate neuroprotective effects.

Anti-inflammatory effect of Ajuga bracteosa Wall Ex Benth. mediated through cyclooxygenase (COX) inhibition

ETHNOPHARMACOLOGICAL RELEVANCE

Ajuga bracteosa Wall Ex Benth. (Labiateae) is described in Ayurveda for the treatment of rheumatism, gout, palsy and amenorrhea.

AIM OF THE STUDY

The aim of present investigation is to study anti-inflammatory activity of Ajuga bracteosa, to understand possible mechanism of action and to identify the constituents responsible for its activity.

MATERIALS AND METHODS

The anti-inflammatory activity of 70% ethanolic extract was evaluated in TPA-induced mouse ear edema assay and in vitro cyclooxygenase (COX)-1 and COX-2 inhibitory activity was determined using EIA kits employing appropriate reference standards. Aajugarin I, lupulin A, withaferin A, reptoside and 6-deoxyharpagide were isolated from the 70% ethanolic extract by silica gel column chromatography.

RESULTS

The 70% ethanol extract of whole plants of Ajuga bracteosa showed a significant (p<0.05) and dose-dependent anti-inflammatory activity in an acute inflammation model at the dose of 0.5 and 1.0 mg/ear. The extract also exhibited a strong in vitro COX-1 and COX-2 inhibitory activity at 25 and 50 μg/mL concentration. Among the isolated compounds 6-deoxyharpagide exhibited highest COX-2 inhibition while rest of the compounds exhibited weak to moderate COX-1 and COX-2 inhibition at 30 μM concentration.

CONCLUSIONS

The results suggest that the 70% ethanol extract of Ajuga bracteosa possesses promising anti-inflammatory activity, which is possibly mediated through inhibition of COX-1 and COX-2 enzymes. The isolated constituents could be responsible in part for its anti-inflammatory and COX inhibitory activity. The study supports traditional use of Ajuga bracteosa for inflammatory diseases.

Screening of antiplasmodial efficacy of Ajuga bracteosa Wall ex. Benth

The rising problem of Plasmodium resistance to the classical antimalarial drugs stresses the need to look for newer antiplasmodial components with effective and new mode of action. In the present study, the traditional medicinal plant Ajuga bracteosa has been screened for its antiplasmodial efficacy. The extract was found to possess significant in vitro antiplasmodial efficacy with an IC(50) of 10.0 μg/ml. Thus, the extract was further evaluated for its in vivo schizontocidal activity and efficacy in terms of survival time in Plasmodium berghei infected BALB/c mice. The extract at 250, 500, and 750 mg/kg/day exhibited significant (p<0.0001) blood schizontocidal activity during established infection with enhanced mean survival time comparable to that of standard drug chloroquine, 5 mg/kg/day. The significant schizontocidal activity and enhanced mean survival time of mice stress the need to identify and characterize active antiplasmodial principle from this plant.

Traditional antimalarial phytotherapy remedies used by the South Coast community, Kenya

AIM OF THE STUDY

This study was conducted to document herbal medicines used in the treatment of malaria as well as the existing knowledge, attitudes and practices related to malaria recognition, control and treatment in South Coast, Kenya.

METHODS

Data was collected using semistructured questionnaires and interviews. A focused group discussion held with the community members, one in each of the study villages supplemented the interview and questionnaire survey.

RESULTS

The respondents were found to have a good understanding of malaria and could distinguish it from other fever types. They were also aware that malaria was spread by mosquitoes. Malaria prevalence was high, and affected individuals an average of four times a year. Community members avoided mosquito bites by using mosquito nets, clearing bushes around their homesteads and burning plant parts to generate smoke. They prevented and treated malaria by taking decoctions or concoctions of traditional herbal remedies. Forty plant species in thirty-five genera distributed in twenty-four families were used as antimalarials in the study area. Five plant species, namely; Heeria insignis Del. (Anacardiaceae), Rottboelia exaltata L.F (Gramineae), Pentanisia ouranogyne S. Moore (Rubiaceae), Agathisanthenum globosum (A. Rich) Hiern (Rubiaceae), and Grewia trichocarpa Hochst ex A. Rich (Tiliaceae) are documented for the first time in South Coast, Kenya, for the treatment of malaria.

CONCLUSIONS

The plants documented in the current study are a potential source for new bioactive compounds of therapeutic value in malaria treatment. The results provide data for further pharmacological and toxicological studies and development of commercial antimalarial phytotherapy products.

Bioactive natural products derived from the East African flora

This review describes bioactive natural products isolated from East African medicinal plants. It includes 211 bioactive compounds from 41 plant species, and cites 116 references.

Chemical constituents of Stereum subtomentosum and two other birch-associated basidiomycetes: an interspecies comparative study

Metabolites of the wood-rotting fungus Stereum subtomentosum Pouzar (Basidiomycetes, order Russulales, family Stereaceae) occurring on birch (Betula pendula Roth) trees were phytochemically investigated for the first time. Three main metabolite chemotypes present in MeOH extracts of the fruit bodies, viz. steroids, fatty acids, and water-soluble sugars, were fractionated, isolated, and identified by 1D/2D NMR-spectroscopic analyses, NMR data comparisons, and chemical correlations combined with GC/MS experiments. Thirteen compounds including two 5 alpha,8 alpha-epidioxy steroids, alpha,alpha'-trehalose, D-arabinitol, D-mannitol, and saturated/unsaturated fatty acids, were identified. Differences among S. subtomentosum and two other birch-associated fungal species, Trametes versicolor (L.: Fr.) Pilát, and Piptoporus betulinus (Bull.: Fr.) P. Karst (Basidiomycetes, order Polyporales, family Polyporaceae) were evaluated as regards the richness and abundance relationships in metabolite profiling.

Evaluation of antiprotozoal and antimycobacterial activities of the resin glycosides and the other metabolites of Scrophularia cryptophila

Resin glycosides are secondary metabolites exclusive to the convolvulaceous plants. In this study, crypthophilic acids A-C (1-3), the first resin glycosides occurring in another family (Scrophulariaceae), and the other constituents of Scrophularia cryptophila were examined for in vitro antiprotozoal and antimycobacterial potentials. Except for crypthophilic acid B (2), all tested compounds exhibited growth-inhibitory effect against Trypanosoma brucei rhodesiense, with l-tryptophan (6) and buddlejasaponin III (7) being the most potent ones (IC(50)'s 4.1 and 9.7 microg/ml). In contrast, the activity towards Trypanosoma cruzi was poor, and only crypthophilic acid C (3), 6 and 7 were trypanocidal at concentrations above 40 microg/ml. With the exception of 2 and 6, all compounds were active against Leishmania donovani. Harpagide (4) and 3 emerged as the best leishmanicidal agents (IC(50)'s 2.0 and 5.8 microg/ml). Only compounds 3, 6 and 7 showed antimalarial activity against Plasmodium falciparum with IC(50) values of 4.2, 16.6 and 22.4 microg/ml. Overall the best and broadest spectrum activity was presented by compounds 3 and 7, as they inhibited all four parasitic protozoa. None of the isolates had significant activity against Mycobacterium tuberculosis (MICs >100 microg/ml) or were toxic towards mammalian (L6) cells. This is the first report of antiprotozoal activity for natural resin glycosides, as well as for harpagide (4), acetylharpagide (5), tryptophan (6) and buddlejasaponin III (7).

Further flavonol and iridoid glycosides from Ajuga remota aerial parts

Five new iridoid glycosides characterised as 6-keto-8-acetylharpagide (1), 6,7-dehydro-8-acetylharpagide (2), 7,8-dehydroharpagide (3), 8-acetylharpagide-6-O-beta-glucoside (4), harpagide-6-O-beta-glucoside (5) together with three flavonol glycosides, myricetin 3-O-rutinoside-4'-O-rutinoside (6), myricetin 3-O-rutinoside-3'-O-rutinoside (7) and isorhamnetin 3-O-rutinoside-7-O-rutinoside-4'-O-beta-glucoside (8) have been isolated from the aerial parts of Ajuga remota. Also isolated were two known compounds ajugarin IV and ajugarin V. Their structures were established using spectroscopic methods including UV, IR, FAB-MS, HR-MS, 1D and 2D NMR techniques.

Antibacterial activity of ergosterol peroxide against Mycobacterium tuberculosis: dependence upon system and medium employed

Ergosterol peroxide, cycloart-23-en-3beta,25-diol, vanillin and 4-hydroxybenzaldehyde have been isolated and characterized from a crude methanol extract of Euphorbia lagascae. Previous studies have shown contradictory results about the antibacterial activity of ergosterol peroxide against Mycobacterium tuberculosis. In order to clarify this question, the activity of this compound was tested against Mycobacterium tuberculosis H37Rv ATCC 27294 strain using two different systems: BACTEC 460TB (Bactec 460) and BACTEC MGIT 960 system (Bactec 960). The results obtained show that significant activity was demonstrable only with the Bactec 460 system. The lack of activity noted with the Bactec 960 system appears to be due to the much faster growth rate of the organism in the medium of this system as opposed to that of the Bactec 460 system. Ergosterol peroxide is also shown by the current study to be devoid of any activity against an antibiotic sensitive ATCC strain of Staphylococcus aureus.

Antiplasmodial and GABA(A)-benzodiazepine receptor binding activities of five plants used in traditional medicine in Mali, West Africa

Extracts of five medicinal plants: Boscia angustifolia, Cissus quadrangularis, Securidaca longipedunculata, Stylosanthes erecta and Trichilia emetica, used traditionally in Malian traditional medicine were screened for in vitro antiplasmodial activity and GABA(A)-benzodiazepine receptor binding activity. Four extracts showed significant antiplasmodial activities, with the dichloromethane extract of leaf of Securidaca longipedunculata being the most active (IC(50) of 7 microg/ml [95% CI: 5-9]). The dichloromethane extract of leaf of Trichilia emetica, in addition to its antiplasmodial activity (IC(50): 12 microg/ml [95% CI: 12-14]), exhibited a good binding activity to the GABA(A)-benzodiazepine receptor, while water and methanol extracts of the same plant did not show any activity. A strong GABA(A)-receptor complex binding activity was observed in the methanol extract of aerial part of Stylosanthes erecta. The results in this study justify some of the traditional indications of the plants investigated and may thus be candidates for Improved Traditional Medicines in Mali.

Diversity and utilization of antimalarial ethnophytotherapeutic remedies among the Kikuyus (Central Kenya)

Plants in Kenya are becoming increasingly important as sources of traditional medicines. The World Health Organization (WHO) has estimated that malaria kills about 2.7 million people every year, 90% of who are from Africa. Malaria continues to be a national concern in Kenya as it plays a major role in the high mortality rates being experienced currently. The use and mis-use of chloroquine to prevent and treat falciparium malaria has led to widespread appearance of chloroquine resistant parasites in Kenya and other tropical countries. These factors and the rising costs of non-chloroquine drugs have made the local people to turn to traditional remedies for management of this menace. This paper examines the current utilization of traditional plant medicines in managing malaria menace in Central Kenya. The results show both indigenous and introduced species are in use indicating traditional medicinal practices in this region are dynamic. In total 58 species in 54 genera and 33 families were identified. The family Rubiaceae was found to have the highest number of reported species. Use of the various taxa is compared between five districts within Central Province of Kenya. The commonest species in this pharmacopoeia are: Caesalpinia volkensii Harms, Strychnos henningsii Gilg, Ajuga remota Benth., Warbugia ugandensis Sprague and Olea europaea L. The first three species are used in all the five districts while the others are restricted in some of the districts. In 74% of the anti-malarial plant species reported in this study, the remedies are obtained in destructive manner and may need conservation measures to ensure sustainable utilization. The results of this study become a basis for selecting plants for further pharmacological and phytochemical studies in developing new and locally relevant anti-malarial agents.

Leishmanicidal activity ofPycnoporus sanguineus

In the search for antiparasite compounds from the Colombian flora, an active compound against Leishmania (Viannia) panamensis amastigotes was isolated from the fungi Pycnoporus sanguineus. The structural elucid-ation was achieved with spectroscopic methods ((1)H and (13)C NMR and MS). This compound was identified as ergosterol 5,8-endoperoxide.

Isolation and identification of neo-clerodane diterpenes from Ajuga remota by high-performance liquid chromatography

In order to explore the suitability of reversed-phase HPLC for the rapid isolation, identification and semi-preparative fractionation of neo-clerodane diterpenes from Ajuga remota, an extract from aerial parts of the plant was examined using a C18 column with UV detection and gradient elution with water:methanol. In addition to the known diterpenes ajugarins I, II, IV and V and clerodin, the presence and chromatographic behaviours of ajugapitin, dihydroajugapitin, dihydroclerodin and deacetylajugarin IV, not previously isolated from A. remota, were established. Presence of the epimeric mixture of 14-hydro-15-hydroxyclerodin (scutecyprol A) was also demonstrated together with that of 14-hydro-15-hydroxyajugapitin, the latter only in trace amounts. The structures of all isolated diterpenes were determined from NMR data. The anti-feedant activities of the isolated compounds against Spodoptera littoralis are also reported here.

Acute and chronic toxicological studies of Ajuga iva in experimental animals

Ajuga iva (L.) Schreber (AI), is widely used in the Moroccan pharmacopoeia as a panacea (cure-all), and specifically for gastrointestinal disorders and diabetes, and as an anthelmintic. No toxicological investigations have been carried out on this plant. We have previously observed that single oral doses (2-14 g/kg) of a lyophilised aqueous extract of AI (AI-extract) in mice or daily oral administration of 10 mg/kg of AI-extract in rats for 2 weeks did not result in any adverse effects. We have now evaluated AI-extract for its behavioural and pharmaco-toxicological effects after acute and chronic administration by the oral and intraperitoneal routes in rats and mice. No toxicity was observed in mice after single oral doses of as high as 14 g/kg of the AI-extract. However, single intraperitoneal injections of the AI-extract (1500-5500 mg/kg BW) produced a dose-dependent increase in adverse effects in the general behaviour and the mortality rate; the LD50 of acute intraperitoneal dose was 3.6 g/kg. In chronic toxicological studies in rats, the AI-extract (administered orally at daily doses of 100, 300 and 600 mg/kg for 3 months), did not cause any changes in haematological and biochemical parameters, with the exception of a transient rise in platelet counts and a short-term decrease in serum glucose levels. Histopathological examination of the brain, liver and the kidneys at the end of the study (3 months) showed normal architecture suggesting no morphological disturbances.