Antimicrobial Importance of Medicinal Plants in Nigeria

Acute and sub-chronic toxicity studies of methanol extract of Trema orientalis (Linn) blume in albino wistar rats

Background

The safety potential of the methanol extract of Trema orientalis (TOM) leaf was evaluated in albino Wistar rats using biochemical, haematological, and histological indices in both acute and sub-chronic toxicity studies.

Methods

The animals were managed following the National Institute of Health (NIH) stipulated protocols for handling laboratory animals. The weight of each animal was recorded upon arrival and monitored throughout the study. The animals were allowed to acclimatize for 14 days, after which they were reweighed and randomly distributed into four groups of three female rats (n=12) for acute toxicity studies. Group A was given distilled water, and Groups B, C, and D were given a single dose of 2000, 4000, and 5000 mg/kg bw TOM extract, respectively. On day 15, each animal was anaesthetized and then euthanized. For the sub-chronic toxicity study, animals were randomly distributed into five groups of eight female rats (n=40). They were dosed daily for 28 days. Group A (Negative control group) was given distilled water. Groups B, C, and D had 200, 400, and 800 mg/kg bw TOM extract and Group E (Vehicle control group) were given 0.25 % of sodium carboxyl methyl cellulose (CMC). Five animals were anaesthetized and then euthanized on day 29, while three animals were kept for recovery evaluation for another two weeks without further administration of the extract. Ten organs were excised from each animal and weighed. The liver and kidney were processed for histopathological studies, while the blood samples were collected for biochemical and haematological assays.

Results

From acute toxicity studies, the LD50 value of TOM extract was estimated to exceed 5000 mg/kg bw via oral passage. From Sub-chronic toxicity studies, biochemical results showed a significant (p < 0.05) reduction in total protein, albumin, globulin, AST, ALP, and ALT in a dose-dependent manner. Histology of the liver and kidney tissues of all the animals except the kidney of the 800 mg/kg group had no visible lesions; this sets the safety dose for TOM at above 400 mg/kg but below 800 mg/kg. Recovery animals had significantly (p < 0.05) increased total protein, total bilirubin, and ALP and decreased albumin and direct bilirubin levels.

Conclusion

This study reports the safety dose of TOM, a reputable medicinal plant extract. This is the first study reporting that the LD50 value of TOM extract exceeds 5000 mg/kg bw via oral passage.

Chinese advances in understanding and managing genitourinary tract infections caused by Mycoplasma genitalium, Mycoplasma hominis, and Ureaplasma urealyticum

Mycoplasma genitalium, Ureaplasma urealyticum and Mycoplasma hominis are bacterial pathogens found in the genitourinary tract, implicated in a range of infections. In women, these infections including pelvic inflammatory disease, vaginitis, infertility, and cervical cancer, while in men, they can cause non-gonococcal urethritis, prostate cancer, among other conditions. These infections are a global health concern, with China identified as a country with a high prevalence. This review provides a comprehensive overview of the epidemiology, causative factors, and diagnostic methods for these three Mycoplasma species with in China. The rise of multi-drug resistance, driven by antibiotics overuse, poses a significant challenge to treatment, complicating patient management. These Mycoplasma species employ unique adhesion mechanisms that trigger a cascade of signal transduction, culminating to inflammatory responses, tissue damage, and the release of toxic metabolites. Here, we delineate the mechanisms of underlying Mycoplasma resistance and propose key therapeutic strategies for these three mycoplasmas in China. This includes a summary of effective antibiotic treatment strategies, and potential combinations of therapeutic to improve cure rates, and a discussion of potential therapeutic approaches using traditional Chinese medicine.

Comparative phytochemical profile and biological activity of three Terminalia species as alternative antimicrobial therapies

Ethnopharmacological relevance

Medicinal plants can help combat antibiotic resistance by providing novel, active molecules. Three plant species of the Terminalia genus are widely used in traditional medicine in the Mouhoun region for the treatment of cutaneous and respiratory diseases. Therefore, it is important to determine the ethnopharmacological potential of bark extracts from the trunks of these three Terminalia species.

Aim of the study

This study compared the phytochemical and biological activities of extracts from three Terminalia species to determine their ethnopharmacology.

Materials and methods

The medicinal properties of the extracts were assessed based on their ability to inhibit the growth of the following microorganisms: Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Candida albicans, Candida krusei, Candida glabrata, and Candida tropicalis. The significant interest in these medicinal plants among the local communities were elucidated by their antioxidant properties and phytochemical composition, along with the detection key bioactive compounds. Major phytochemical groups and phenolic compounds were determined using high-performance liquid chromatography with a diode array detector. These phytochemical findings were validated by evaluating the antioxidant capacity of the extracts using DPPH, FRAP, and ABTS assays.

Results

Hydroethanolic, ethanolic, and hexane extracts from the bark of three Terminalia species inhibited the growth of both bacteria and fungi, as evidenced by their minimum inhibitory concentrations (MICs).The findings showed that Terminalia species were most effective against various tested bacteria and fungi, with MICs ranging from 0.1 to 6.25 mg/mL. Terminalia avicennioides, Terminalia macroptera, and Terminalia laxiflora extracts demonstrated 50 % inhibition of DPPH at concentrations ranging from 0.04 to 0.6 mg/mL. Phytochemical analysis revealed the presence of several families of chemical compounds, such as total phenolics and flavonoids. Phenolic compounds identified by HPLC in ethanolic extracts of T. avicennioides, such as isorhamnetin, quercetin, and ferulic acid, are recognised for their antimicrobial and antioxidant properties.

Conclusion

These findings establish an ethnobotany for these three Terminalia species, with their chromatographic characteristics facilitating the identification of key molecules of interest. The ethanolic extract of T. avicennioides can be used in phytomedicinal formulations against bacterial (P. aeruginosa and S. aureus) and fungal (C. albicans and C. glabrata) infections, both of which are recurrently recorded in certain skin and respiratory tract diseases.

In vitro antibacterial and antioxidant activity of flavonoids from the roots of Tephrosia vogelii: a combined experimental and computational study

Tephrosia vogelii is a traditional medicinal plant used to treat hypertension, diarrhea and urinary disorders. Silica gel chromatographic separation of CH2Cl2/MeOH (1:1) roots extract of T. vogelii afforded seven compounds namely; β-sitosterol (1a), stigmasterol (1b), 6a, 12a-dehydro-deguelin (2), tephrosin (3), maackiain (4), obovatin (5) and 6-oxo, 6a, 12a-dehydro-deguelin (6). GC-MS analysis of essential oils from the root of T. vogelii displayed a total of 17 compounds of which cis-nerolidol (41.7 %) and cadinol (19.7 %) were the major constituents. CH2Cl2/MeOH (1:1) extract, MeOH extract, maackiain (4) and obovatin (5) showed moderate inhibitory activity against Pseudomonas aeruginosa with MIC value of 0.5, 0.66, 0.83 and 0.83 mg/mL, respectively, compared to ciprofloxacin (MIC of 0.078 μg/mL). 6a, 12a-dihydro-deguelin (2), and 6-oxo, 6a, 12a-dehydro-deguelin (6) displayed significant activity against S. epidermis with MIC values of 0.66 mg/mL. Tephrosin (3) and maackiain (4) also showed moderate antibacterial activity against Staphylococcus aureus and Proteus mirabilis with MIC values of 0.83 and 0.5 mg/mL, respectively, compared to ciprofloxacin (0.312 μg/mL). The radical scavenging activity results indicated that tephrosin (3), obovatin (5) and 6-oxo, 6a, 12a-dehydro-deguelin (6) showed potent DPPH scavenging activity with IC50 values of 10.97, 10.43 and 10.73 μg/mL, respectively, compared to ascorbic acid (IC50 of 5.83 μg/mL). The docking prediction results revealed that 6a, 12a-dehydro-deguelin (2) displayed the best binding energy of -8.1 kcal/mol towards pyruvate kinase of S. aureus (PDB ID: 3T07) and -7.9 kcal/mol towards P. mirabilis urease (PDB ID: 1E9Y) and DNA gyrase B of Escherichia coli (PDB: 4F86) receptors compared to ciprofloxacin (-7.2 to -8.0 kcal/mol). Maackiain (4) and obovatin (5) displayed the minimum binding energy of -7.9 and -8.2 kcal/mol towards the LasR protein of P. aeruginosa (PDB: ID 2UV) and S. epidermidis FtsZ (PDB: ID 4M8I), respectively. The SwissADME drug-likeness and Pro Tox II toxicity prediction results indicated that compounds (2-6) obeyed Lipinski's rule of five with 0 violations and none of them were found to be hepatotoxic, mutagenic, and cytotoxic, respectively. The in vitro assessment results supported by the in silico analysis revealed that crude extracts and isolated compounds showed promising antibacterial and antioxidant activity, which proves the therapeutic potential of the roots of T. vogelii.

Comprehensive Analysis of Curcumin Zinc Oxide Nanoparticles, Synthesis, Characterization, and Cytogenotoxic Profiling

Curcumin from turmeric (Curcuma longa) has traditionally been used due to its pharmacological properties, such as anticancer, anti-inflammatory, cholesterol-lowering, and antioxidant activities, but has had limitations in use due to low bioavailability. Nanoparticles have protuberant efficacies to diagnose or cure a variety of diseases, including tumors, by fine-tuning their size, structure, and physicochemical characteristics. This study aims to develop a new dosage form of curcumin nanoparticles with zinc oxide to enhance its therapeutic efficacy against cancer and cause no damage to genetics. Curcumin zinc oxide nanoparticles were prepared and characterized by using a Zeta sizer, ultraviolet (UV)-spectrophotometer, scanning electron microscope (SEM), and Fourier transform infrared (FTIR) spectroscopy. Different concentrations range from 40 to 0.078 μg/mL, and these nanoparticles were evaluated for their anticancer activity by colorimetric analysis (MTT assay) on normal (Vero) and cancerous cell lines (MCF-7) and genotoxicity by the comet assay. The spherical-shaped curcumin zinc oxide nanoparticles of 189 nm size were prepared with characteristic functional groups. The selectivity index of curcumin zinc oxide nanoparticles, calculated from IC50 values, is 4.60 > 2.0, showing anticancer potential comparable to tamoxifen. The genetic damage index of the highest concentration (40 μg/mL) of curcumin zinc oxide nanoparticles was 0.08, with a percent fragmentation of 8%. The results suggest that nanoparticles of curcumin zinc oxide produced better anticancer effects and did not cause any significant damage to the DNA. Consequently, further research is required to ensure the development of a safe and quality dosage form of nanoparticles for proper utilization.

Antibacterial Activity and Mechanism of Action of Osthole against Listeria monocytogenes

The purpose of this study was to investigate the antibacterial activity and mechanism of action of osthole against Listeria monocytogenes. The antibacterial activity of osthole was evaluated by determining the minimum inhibitory concentration (MIC) and growth curve. Cell morphology, membrane permeability, membrane integrity, bacterial physiology, and metabolism were explored using different methods to elucidate the mechanism of action of osthole. It was shown that the MIC of osthole against L. monocytogenes was 62.5 μg/mL and it inhibited the growth of L. monocytogenes effectively in a concentration-dependent manner. Scanning electron microscopy (SEM) images demonstrated morphology changes of L. monocytogenes, including rough surface, cell shrinkage, and rupture. It was found that extracellular conductivity and macromolecule content were increased significantly in the presence of osthole, indicating the disruption of cell membrane integrity and permeability. Laser confocal microscopy results supported the conclusion that osthole caused severe damage to the cell membrane. It was also noticed that osthole depleted intracellular adenosine triphosphate (ATP), inhibited Na+-K+-ATPase and Ca2+-Mg2+-ATPase activity, and promoted the accumulation of intracellular reactive oxygen species (ROS), leading to cell death. This study suggests that osthole is a promising antibacterial agent candidate against L. monocytogenes, and it shows potential in the prevention and control of foodborne pathogens.

Phytochemical and antimicrobial properties of different plants and in silico investigation of their bioactive compounds in wound healing and rheumatism

In the current study the assessment of the antimicrobial and phytochemical properties of Cassia fistula, Musa paradisiaca, Ficus religiosa and Murraya koenigii plants extracts was carried out. The antibacterial potential of these plants extracts was tested against S. aureus and E. coli. The Cassia fistula and Ficus religiosa leaves showed the larger zone of inhibition in aqueous and butanolic extract respectively against Escherichia coli. Musa paradisiaca and Murraya koenigii leaves showed larger zone of inhibition in ethanolic extract against S. aureus. Qualitative phytochemical analysis showed the presence of alkaloids, flavonoids, phenols, terpenoids, steroids, glycosides, saponins, carbohydrates, proteins and tannins in all extracts while phylobatannins, emodins, anthocyanins and leucoanthocyanins were not present in these extracts. Quantitative phytochemical analysis showed the highest alkaloid content in the Murraya koenigii leaves. Highest tannin content and flavonoid content was found in Ficus religiosa leaves, while highest phenolic content was found in case of Cassia fistula. In addition to this antioxidant potential of all the extracts was determined. Musa paradisiaca leaves showed highest antioxidant potential as compared to other plant extracts. In silico analysis of bioactive components present in plant extracts was performed by molecular docking. The rutin and Glu from Musa paradisiaca and Murraya koenigii respectively, were docked with Glycogen Synthase Kinase 3 beta (1GSK-3beta) protein. Quercetin and rutin from Cassia fistula and Ficus religiosa respectively, were docked with C- reactive protein (CRP). The tested bioactive compounds showed good binding affinity with significant number of hydrogen bonds and can be used as a good alternative of synthetic drugs to treat rheumatism and wounds.

Chemical composition, antifungal, and anti-virulence action of the stem bark of Hancornia speciosa Gomes (Apocynaceae) against Candida spp

ETHNOPHARMACOLOGICAL RELEVANCE

Hancornia speciosa Gomes is a fruit and medicinal species used for treating infectious diseases of the genitourinary system. However, its mechanism of action against microbes is still not fully understood. Infections in the genitourinary system caused by Candida spp. are associated with its fungal resistance and pathogenicity. New plant-derived compounds are an alternative to fight these Candida infections.

AIM OF THE STUDY

The objective of this study was to evaluate the anti-Candida effects of extracts of the stem bark of H. speciosa. This research investigated the chemical composition of sulfuric ether (EEHS) and methanolic (MEHS) extracts, their drug-modifying action on fluconazole, and their anti-virulence action on the morphological transition of Candida species.

MATERIALS AND METHODS

The extracts (EEHS and MEHS) of the stem bark of H. speciosa were chemically characterized via qualitative phytochemical screening and by liquid chromatography coupled with mass spectrometry (UPLC-MS-ESI-QTOF). The extracts were evaluated regarding their antifungal effects and fluconazole-modifying activity against Candida albicans, Candida krusei, and Candida tropicalis using the broth microdilution method. Additionally, the study evaluated the inhibition of fungal virulence in Candida species through morphological transition assays.

RESULTS

The phytochemical screening revealed the presence of anthocyanidins, anthocyanins, aurones, catechins, chalcones, flavones, flavonols, flavanones, leucoanthocyanidins, tannins (condensed and pyrogallic), and xanthones in both extracts of the stem bark of H. speciosa. The UPLC-MS-ESI-QTOF analysis identified the same compounds in both extracts, predominating phenolic compounds. Some compounds were first time recorded in this species: gluconic acid, cinchonain IIb, cinchonain Ib isomer, and lariciresinol hexoside isomers. Most of the intrinsic antifungal activity was observed for the MEHS against C. krusei (IC50: 58.41 μg/mL). At subinhibitory concentrations (MC/8), the EEHS enhanced the action of fluconazole against all Candida strains. The MEHS exhibited greater efficacy than fluconazole inhibiting C. krusei growth. The EEHS completely inhibited hyphae appearance and reduced pseudohyphae formation in C. albicans.

CONCLUSION

The stem bark of H. speciosa is a rich source of bioactive compounds, especially phenolic. Phenolic compounds can have important roles in fighting infectious diseases of the genitourinary system, such as candidiasis. The extracts of H. speciosa improved the action of the drug fluconazole against Candida species, inhibited hyphae appearance, and reduced pseudohyphae formation. The results of this study can support the development of new therapeutics against resistant strains of Candida.

Potential of Flavonoids as Promising Phytotherapeutic Agents to Combat Multidrug-Resistant Infections

BACKGROUND

Considering the limited number of current effective treatments, Multidrug- Resistant (MDR) illnesses have grown to be a serious concern to public health. It has become necessary to look for new antimicrobial drugs because of the emergence of resistance to numerous kinds of antibiotics. The use of flavonoids is one phytotherapeutic strategy that has been researched as a potential remedy for this issue. Secondary plant compounds called flavonoids have been found to have an antibacterial effect against resistant microorganisms.

OBJECTIVE

This review seeks to give readers a glimpse into contemporary studies on flavonoids' potential to fight MDR infections.

METHODS

A systematic search was conducted on electronic databases (PubMed, Scopus, and Google Scholar) using relevant keywords such as flavonoids, MDR infections, antimicrobial activity, and resistance microbes. Studies that investigated the antimicrobial activity of flavonoids against resistant microbes were included in this review.

RESULTS

Most research found that flavonoids have antibacterial efficacy against resistant microorganisms, and some also showed that they have synergistic benefits with traditional antibiotics. The flavonoids quercetin, kaempferol, apigenin, and luteolin were the most often investigated ones. According to research, flavonoids affect microbial gene expression, inhibit microbial enzymes, and disrupt the integrity of microbial cell membranes. Additionally, a few studies have noted the flavonoids' low toxicity and safety.

CONCLUSION

For the treatment of infections that are resistant to many drugs, flavonoids constitute a promising class of phytotherapeutic agents. To develop flavonoid-based treatment methods for treating MDR illnesses and assess the potential of flavonoids as adjuvants to conventional antimicrobial drugs, more study is required.

Molecular Mechanics with Generalized Born Surface Area (MMGBSA) Calculations and Docking Studies Unravel some Antimalarial Compounds Using Heme O Synthase as Therapeutic Target

The enzyme Heme O Synthase (HOS) is essential for producing heme A and heme O, which are critical for defense against reactive oxygen species, drug detoxification, gas synthesis, transport, and electron transport in Plasmodium species. It has become vital to discover inhibitory molecules/compounds/medicines that target the synthesis of heme due to the emergence of drug‐resistant strains of Plasmodium falciparum. Therefore, in this study, we employed molecular mechanics with Generalized Born surface area (MMGBSA) calculations and docking studies to investigate potential antimalarial compounds targeting HOS from antimalarial botanicals. Screening these compounds, we have identified 2 compounds; Meliantrol and Tamarixetin with better binding affinities (−8.4 Kcal/mol and −8.3 Kcal/mol respectively) than the current standard inhibitor(Inabenfide) of HOS (−8.0 Kcal/mol). The MMGBSA calculations provided insight into the thermodynamics of the binding process and helped identify key interactions responsible for the stability of the HOS‐ligand complex. In addition, the 2 compounds were further screened comparatively with the standard HOS inhibitor considering their protein‐ligand interaction profile and ADMET profile and these 2 selected compounds outperformed Inabenfide. Our results predict that these compounds are potential drug candidates with domiciled therapeutic functions against Malaria therefore, open doors for more experimental validations for drug development.

Predicting Plasmodium falciparum kinase inhibitors from antimalarial medicinal herbs using computational modeling approach

Malaria remains a significant public health challenge, with resistance to available drugs necessitating the development of novel therapies targeting invasion-dependent proteins. Plasmodium falciparum calcium-dependent protein kinase 1 (PfCDPK-1) is essential for host erythrocyte invasion and parasite asexual development. This study screened a library of 490 compounds using computational methods to identify potential PfCDPK-1 inhibitors. Three compounds; 17-hydroxyazadiradione, Picracin, and Epicatechin-gallate derived from known antimalarial botanicals, showed potent inhibitory effects on PfCDPK-1. These compounds exhibited better binding affinities (-8.8, -9.1, -9.3 kCal/mol respectively), pharmacokinetics, and physicochemical properties than the purported inhibitory standard of PfCDPK-1, Purfalcamine. Molecular dynamics simulations (50 ns) and molecular mechanics analyses confirmed the stability and binding rigidity of these compounds at the active pocket of PfCDPK-1. The results suggest that these compounds are promising pharmacological targets with potential therapeutic effects for malaria treatment/management without undesirable side effects. Therefore, this study provides new insights into the development of effective antimalarial agents targeting invasion-dependent proteins, which could help combat the global malaria burden.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40203-023-00175-z.

Recent Updates on the Antimicrobial Compounds from Marine-Derived Penicillium fungi

In this review, 72 compounds isolated from marine-derived Penicillium fungi and their antimicrobial activities are reviewed from 2020 to 2023. According to their structures, these compounds can be divided into terpenoids, polyketides, alkaloids and other structural compounds, among which terpenoids and polyketides are relatively large in number. Some compounds have powerful inhibitory effects against different pathogenic bacteria and fungi. This review aims to provide more useful information and enlightenment for further efficient utilization of Penicillium spp. and their secondary metabolites.

Bactericidal and Antioxidant Potential of Moringa oleifera Capped Silver Nanoparticles under Varied Conditions

Microbial infections have consistently been identified as one of the major threats to global health. In this regard, the current study was designed to synthesize and evaluate the antibacterial activity of Mo‐AgNPs at various concentrations (2, 4, and 8 mg/mL), temperatures (4 °C, 25 °C, 37 °C, and 85 °C) and pH (4, 7, and 11) against Gram‐negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Aeromonas veronii) and Gram‐positive bacteria (Staphylococcus aureus, Bacillus subtilis) by the well diffusion method as well as antioxidant potential using DPPH assay at 2 mg/mL and 4 mg/mL. Fabrication of Mo‐AgNPs was authenticated by UV–visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and X‐ray diffraction (XRD). Mo‐AgNPs produced a significant zone of growth inhibition (21.0±0.3 mm) against B. subtilis at 8 mg/mL. At 25 °C, a significant zone of growth inhibition (21.0±0.8 mm) was measured against E. coli. Similarly, at pH 4, Mo‐AgNPs showed significantly highest growth inhibition zones of 12.0±7.5 mm, 12.0±6.3 mm, and 12.0±9.8 mm against P. aeruginosa, K. pneumoniae, and A. veronii, respectively. The present study results indicated that Mo‐AgNPs are stable under varied conditions. Significant free radical scavenging activity (82±0.5 %) of Mo‐AgNPs at 4 mg/mL was observed, which revealed the antioxidant potential of the Mo‐AgNPs.

Preliminary Study on the Antibacterial Activities and Antibacterial Guided Fractionation of Some Common Medicinal Plants Practices in Itum Bahal, Kathmandu Valley of Nepal

The aim of this study was to evaluate the antibacterial activities of selected medicinal plant practices by a traditional healer of the Newar community in Itum Bahal, Kathmandu, Nepal. The antibacterial activities of the methanolic extract (1 mg/disc) of fifteen medicinal plants were screened against two Gram-positive bacteria (Staphylococcus aureus ATCC 25923 and Bacillus subtilis ATCC 6633) and two Gram-negative bacteria (Escherichia coli ATCC 25922 and Salmonella typhi CCM 5445) using the disc diffusion method. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were calculated for the different fractions (hexane, chloroform, ethyl acetate, acetonitrile, and acetone) of the plants having a significant antimicrobial effect. Only Quercus infectoria G. Olivier (galls) and Mallotus repandus (Willd.) Müll.Arg. (seeds) exhibited prominent antibacterial effects. The acetone fraction from Q. infectoria had the strongest antibacterial effect, with a 41.00 mm inhibition zone against S. aureus. In contrast, the ethyl acetate fraction in M. repandus exhibited the highest efficacy, producing a 29.00 mm inhibition zone against S. typhi. In a similar manner, in the case of Q. infectoria, the acetoe fraction depicted the lowest MIC (0.19 mg/mL) and MBC (0.98 mg/mL) values against S. aureus, whereas the ethyl acetate fraction of M. repandus was most significant, showing the lowest MIC and MBC of 0.25 and 0.53 mg/mL, respectively, against S. typhi. This study suggested that the acetone extract of Q. infectoria galls can be used as a potential source against Gram-positive bacteria, whereas the ethyl acetate extract of M. repandus seeds could serve as a useful source to inhibit Gram-negative bacteria. Furthermore, extensive scientific investigation is mandatory to ensure the proper use of folk medicines.

Chemical Constituents from Ficus sagittifolia Stem Bark and Their Antimicrobial Activities

The phytochemical investigation of the ethylacetate fraction of an ethanolic extract obtained from the stem bark of Ficus sagittifolia (Moraceae) led to the isolation of four flavonoids: (2R)-eriodictyol (1), 2'- hydroxygenistein (2), erycibenin A (3), and genistein (4); a dihydrobenzofuran: moracin P (5); a coumarin: peucedanol (6); and an apocarotenoid terpenoid: dihydrophaseic acid (7). These were identified via 1D and 2D nuclear magnetic resonance spectroscopy (NMR) and ultra-high-resolution liquid chromatography-quadrupole time-of-flight mass spectroscopy (UHPLC-QTOF MS). Moracin P (5) is being reported for the first time in the genus Ficus, while the others are known compounds (1-4 and 6-7) isolated previously from the genus but being reported for the first time from the species F. sagittifolia. Their antimicrobial activity against various pathogens (five bacteria: Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, and Salmonella typhi; two fungi: Aspergillus niger and Candida albicans) was tested. The mixture of genistein and moracin P (4+5) exhibited strong activity against K. pneumoniae (MIC < 0.0039 mg/mL), whereas dihydrophaseic acid (7) was the most active against P. aeruginosa and A. niger (MIC = 0.0078 and <0.0039 mg/mL, respectively). These compounds might be considered potential antimicrobial agents with the potential to be starting points for the development of antimicrobial drugs.

A scoping review of African natural products against gastric ulcers and Helicobacter pylori

ETHNOPHARMACOLOGICAL RELEVANCE

African traditional medicine is one of the oldest and most diverse practices for treating ailments and numerous natural products have been recommended for gastric ulcer treatment. Helicobacter pylori is the main causative organism implicated in several diseases, most notably in causing inflammation and the onset of gastric ulcers. Current H. pylori treatment methods are losing efficacy as H. pylori rapidly gains resistance to antibiotics. Hence, a search into natural products and their historical traditional efficacy for the treatment of gastric ulcers is of interest.

AIM OF THE STUDY

This review aimed to summarise the African use of natural products, including medicinal plants noted in ethnobotanical reviews, used traditionally to treat gastric ulcers, and highlights the investigations into the anti-H. pylori activity of medicinal plants and bee products found in Africa.

METHODOLOGY

A systematic review was carried out to identify natural products, including those used traditionally in Africa to treat gastric ulcers, and to correlate this with scientific investigations into the anti-H. pylori activity of natural products used in Africa.

RESULTS

A total of 107 literature sources describing the traditional use of medicinal plants in gastric ulcer treatment were found, from which 360 medicinal plants were identified. Of the plants used traditionally for gastric ulcer treatment, 11% were investigated either in vitro or in vivo for anti-ulcer and anti-H. pylori activity. Of the 122 medicinal plants eliciting antimicrobial or anti-ulcer activity, Hibiscus sabdariffa L. calyx extract and Terminalia macroptera Guill. & Perr. root extract were found to have the most noteworthy antimicrobial activity, with minimum inhibitory concentrations (MICs) of 0.01 mg/mL and 0.03 mg/mL respectively. The essential oils of Piper longum L. and Pachira aquatica Aubl. displayed the most notable in vitro anti-H. pylori activity (MIC of 0.01 mg/mL and 0.02 mg/mL). Several in vivo studies found medicinal plant extracts effective in reducing the H. pylori load along the gastric mucosa. The South African honey variants, Pure Honey and Champagne Royal Train (common names given by supplier) were the most antimicrobially effective (MIC of 0.01-10.0%, 0.63-10.00% v/v) in inhibiting H. pylori when assessed in vitro.

CONCLUSION

These results highlight the potential of natural products to inhibit H. pylori growth and serve as a possible stepping-stone in understanding the management of ulcers. Furthermore, effective natural product treatment or prophylactic use for preventing H. pylori growth may provide a more affordable option for African populations.

Potential Use of African Botanicals and Other Compounds in the Treatment of Methicillin-Resistant Staphylococcus aureus Infections

Infections caused by the group of Staphylococcus bacteria are commonly called Staph infections, and over 30 types of Staphylococcal bacteria exist with Staphylococcus aureus causing about 90% of the infections from the genus. Staphylococcus aureus (S. aureus) is a major cause of both hospital- and community-acquired infections with major concern arising from its strain of species that is resistant to many antibiotics. One of such strain is the Methicillin-resistant Staphylococcus aureus (MRSA) that has been described to be a resistance to methicillin drugs. Another is glycopeptides-resistant emerging from the increased use of glycopeptides drugs. This continuous emergence and spread of new resistant strains of S. aureus is a major challenge which makes the search for novel anti-resistant agents imperative. The development of vaccines from natural and synthetic products is some of the measures being proposed for the protection against the infections. Also, the development of monoclonal or polyclonal antibodies for passive immunization is sought for, and attentions with regard to arriving at successful trials have been directed back to medicinal plant research as an alternative. This review discusses the treatment strategies of MRSA, the antibacterial property of various medicinal plants, and the influence of their active compounds on methicillin-resistant S. aureus (MRSA), as well as to recommend the path to future research in this area.

Daniellia oliveri (Rolfe) Hutch and Dalziel: Antimicrobial Activities, Cytotoxicity Evaluation, and Phytochemical Identification by GC-MS

During a previous study that identified plants used in traditional medicine in Togo to treat infectious diseases, Daniellia oliveri was specifically reported to treat intertrigo and candidiasis. Consequently, to explore the anti-infective potential of this plant, we investigated the antibacterial and the antifungal activity of the plant's parts, as well as the cytotoxic activities of raw extracts and subsequent fractions, and the chemical composition of the most active fractions. In order to evaluate the antimicrobial activity, MICs were determined using the broth dilution method. Then, the most active fractions were evaluated for cytotoxicity by using normal human cells (MRC-5 cells) via the MTT assay. Finally, the most active and not toxic fractions were phytochemically investigated by GC-MS. Interestingly, all the raw extracts and fractions were active against the bacteria tested, with MICs ranging from 16 µg/mL to 256 µg/mL, while no antifungal activity was observed at 256 µg/mL, the highest tested concentration. Moreover, no toxicity was observed with most of the active fractions. The subsequent chemical investigation of the most interesting fractions led to identifying terpenes, phytosterols, phenolic compounds, and fatty acids as the main compounds. In conclusion, this study demonstrated that D. oliveri possesses valuable antibacterial activities in accordance with traditional use.

Process optimization, scale-up studies, economic analysis and risk assessment of phenolic rich bioactive extracts production from Carica papaya L. leaves via heat-assisted extraction technology

This work investigated the influence of process variables of extraction temperature (35–55 °C), solid to liquid ratio (1:20–1:50 g/mL) and time (100–200 min) on the total phenolic content (TPC) and yield (EY) of Carica papaya leaves (CPL) extracts using Box-Behnken experimental design available in Design Expert software. Bi-objective process optimization was also carried out using the desirability function algorithm. The optimum process variables were later used to design an integrated process for the production of CPL extracts with the assistance of SuperPro Designer software. Scale-up studies and economic analysis for CPL extracts production were investigated in the range of 0.638–20.431 × 10³ kg CPL extracts/y to determine the most economically feasible production capacity based on the minimum unit production cost (UPC) of CPL extracts. The risk and sensitivity analyses of the most economically feasible production scale were carried out using the Monte Carlo simulation in Oracle Crystal Ball software. Process variables had notable influences on the TPC and EY of CPL extracts. The extraction temperature of 35 °C, solid to liquid ratio of 40.25 g/mL and time of 100 min gave the optimum TPC of 74.65 mg GAE/g d.b and EY of 18.76 % (w/w). HPLC results indicated that CPL extracts were rich in gallic, betulinic, chlorogenic, ellagic, ferulic and caffeic acids. The designed integrated process showed similar behavior with the laboratory scale of 0.18758 g CPL extracts/batch. The preliminary techno-economic analysis indicated that plant capacity has a strong dependence on the material & energy demands and process economics. Plant capacity of 19.857 × 10³ kg CPL extracts/y possessed the least UPC and was selected as the most economically feasible scale. The certainty of obtaining base case UPC value of 525.21 US$/kg CPL extracts was 75.20%. Sensitivity analysis showed that extracts recovery, CPL/water, centrifuge purchase cost, extraction time, extractor purchase cost and extraction temperature contributed -5.3 %, +42.8%, +4.0%, +47.1%, +0.1%, and +0.5%, respectively to the variance in UPC of CPL extracts.

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Carica papaya leaves (CPL) extracts are rich in polyphenols.

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Heat assisted extraction technology was capable of recovering CPL extracts.

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Industrial extracts scale-ups were achievable using SuperPro Designer software.

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Plant capacity of 19.857 × 10³ kg extracts/y was selected most economical scale.

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The 525.21 US$/kg extracts unit production cost base case certainty was 75.20%.

Anti-Inflammatory Medicinal Plants of Bangladesh—A Pharmacological Evaluation

Inflammatory diseases are considered major threats to human health worldwide. In Bangladesh, a number of medicinal plants have been used in traditional medicine from time immemorial in the treatment of diverse diseases, including inflammatory disorders. This assignment aims at providing the status of the medicinal plants of Bangladesh which are traditionally used in the management of inflammatory disorders and are investigated for their anti-inflammatory prospects using different preclinical studies and future research directions. The information of medicinal plants assembled in this review was obtained from a literature search of electronic databases such as Google Scholar, PubMed, Scopus, Web of Science and ScienceDirect up to December, 2020 from publications on plants investigated for their anti-inflammatory activities, in which the place of plant sample collection was identified as Bangladesh. Keywords for primary searches were “anti-inflammatory,” “Bangladeshi,” and “medicinal plants.” Criteria followed to include plant species were plants that showed significant anti-inflammatory activities in 1) two or more sets of experiments in a single report, 2) same or different sets of experiments in two or more reports, and, 3) plants which are traditionally used in the treatment of inflammation and inflammatory disorders. In this study, 48 species of medicinal plants have been reviewed which have been used in traditional healing practices to manage inflammatory disorders in Bangladesh. The mechanistic pathways of the in vivo and in vitro study models used for the evaluation of anti-inflammatory properties of plant samples have been discussed. Selected plants were described in further detail for their habitat, anti-inflammatory studies conducted in countries other than Bangladesh, and anti-inflammatory active constituents isolated from these plants if any. Medicinal plants of Bangladesh have immense significance for anti-inflammatory activity and have potential to contribute toward the discovery and development of novel therapeutic approaches to combat diseases associated with inflammation. However, the plants reviewed in this article had chiefly undergone preliminary screening and require substantial investigations including identification of active molecules, understanding the mechanism of action, and evaluation for safety and efficacy to be followed by the formulation of safe and effective drug products.

Antibacterial activities of plant leaf extracts against multi-antibiotic resistant Staphylococcus aureus associated with skin and soft tissue infections

Background

The antibacterial activities of aqueous leaf extracts of Moringa oleifera, Vernonia amygdalina, Azadirachta indica and Acalypha wilkesiana against multidrug resistance (MDR) Staphylococcus aureus associated with skin and soft tissue infections were investigated.

Methods

Staphylococcus aureus (n = 183) from the skin and soft tissue infections with evidence of purulent pus, effusions from aspirates, wounds, and otorrhea were biotyped, and evaluated for biofilm production. The phenotypic antibiotic resistance and MDR strains susceptibility to plant leaves extract were determined using disc diffusion and micro-broth dilution assays respectively. The correlation of plant extract bioactive components with inhibitory activities was determined.

Results

High occurrence rate of S. aureus were recorded among infant and adult age groups and 13.2% mild biofilm producers from the wound (p < 0.05). Of 60.2% MDR strains with overall significant MARI of more than 0.85 (p < 0.05), high resistant rates to linozidine (92.7%; 95% CI:7.27–10.52), ofloxacin (94.2%; 95% CI:6.09–8.15), chloramphenicol (91.2%; 95% CI:6.11–8.32), gentamicin (97.3%; 95% CI:6.20–8.22), ciprofloxacin (92.7%; 95% CI: 5.28–7.99) and vancomycin (86.6%; 95% CI:6.81–9.59) were observed. Vernonia amygdalina and Azadirachta indica showed significant antimicrobial activity at 100 mg/ml and 75 mg/ml, with low susceptibility of less than 10% to 25 mg/ml, 50 mg/ml, and 75 mg/ml Moringa oleifera. Alkaloids, saponin and terpenoids were significant in Moringa oleifera, Acalypha wilkesiana, Azadirachta indica and Vernonia amygdalina leaves extracts (p < 0.05). High inhibitory concentrations at IC50; 3.23, 3.75 and 4.80 mg/ml (p = 0.02, CI: − 0.08 – 11.52) and IC90; 12.9, 7.5, and 9.6 mg/ml (p = 0.028, CI: 2.72–23.38) were shown by Acalypha wilkesiana, Vernonia amygdalina and Moringa oleifera respectively. Comparative outcome of the plant extracts showed Acalypha wilkesiana, Vernonia amygdalina and Moringa oleifera to exhibit significant inhibition activities (p < 0.05) compared to other extracts. Significant median inhibitory concentration (15.3 mg/ml) of Azadirachta indica were observed (p < 0.01) and strong associations of phytochemical compounds of Azadirachta indica (eta = 0.527,p = 0.017), Vernonia amygdalina (eta = 0.123,p = 0.032) and Acalypha wilkesiana (eta = 0.492,p = 0.012) with their respective inhibitory values.

Conclusion

Observed high occurrence rate of skin and soft tissue infections caused by biofilm-producing MDR S. aureus requires alternative novel herbal formulations with rich bioactive compounds from Moringa oleifera, Acalypha wilkesiana, Azadirachta indica and Vernonia amygdalina as skin therapeutic agents.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03527-y.

A Comprehensive Review on Current perspectives of Flavonoids as antimicrobial agent

Flavonoids are the secondary plant metabolites with diversities of pharmacological activities like antioxidant, anticancer, anti-inflammatory, hepatoprotective, free radical scavenging activity and antiviral activities. Flavonoids have also been proved as a major contributor to the antimicrobial phytochemicals. Being the major substituent of antibiotics today flavonoids has attained high attention as there is increase in persistence of untreatable microbial infections due to microbial resistance. This review demonstrates the screening, isolation of extracts and derivatisation of various flavonoids and their evaluation for antimicrobial potency. Recent advancements of various derivatives of flavonoids having antimicrobial activity has also been discussed in this review. This review helps researchers to get vast knowledge about flavonoids and also give an idea for current scenario of flavonoids and its applications as antimicrobial agent.

Sauropus androgynus (L.) Merr.: a multipurpose plant with multiple uses in traditional ethnic culinary and ethnomedicinal preparations

Various plants form the basis of multiple traditional ethnic cuisines and ethnomedicinal practices across the globe. The ethnic cuisines cater to the nutritional, dietary and medicinal requirements of the tribal and rural communities even today. Using literature from various scholarly databases, this study was conducted to consolidate a comprehensive review on the use of Sauropus androgynus (L.) Merr. in various traditional ethnic cuisines and ethnomedicinal preparations across the globe. The survey shows that it is used in multiple ethnic cuisines and is variously known in different countries and among the communities. Further, it possesses multiple nutritional and ethnomedicinal properties. Considering its importance in ethnic foods and ethnomedicinal preparations, it is important to investigate the nutritional composition, phytochemical constitution and pharmacological basis of ethnomedicinal uses. Therefore, we further compiled this information and found that it is a rich source of both micro- and macronutrients and packed with several bioactive compounds. Survey of pharmacological studies on its traditional medicinal uses supports its ethnomedicinal properties. Despite its importance in traditional food and ethnomedicinal systems, it remains underexplored. Limited information on the toxicity of its various extracts shows that further studies should be conducted to understand its safety aspects. Further clinical studies to prospect possible drug candidates from it should be attempted.

Potentials of Medicinal Plant Extracts as an Alternative to Synthetic Chemicals in Postharvest Protection and Preservation of Horticultural Crops: A Review

Horticultural crops undergo various physiological and biochemical changes that lead to undesirable physiological disorders, decay and subsequent economic losses during storage. Quality degradation of horticultural crops is mainly caused by postharvest pathogens such as Botrytis cinerea and Penicillium spp., etc. The application of synthetic fungicides remains the most effective method to control postharvest pathogens. However, their use is becoming increasingly restricted internationally due to health concerns and consumers’ requests for safe and natural alternatives. This has led researchers to investigate natural flora as one of the alternatives to be used in crop protection and preservation. Various medicinal plant parts have different phytochemicals and antioxidants that can be used in crop protection and preservation. Extracts from plants such as Ruta chalepensis, Eucalyptus globulus, etc., have proven to be effective in controlling postharvest pathogens of horticultural crops and increased their shelf life when used as a substitute for synthetic chemicals. Furthermore, extracts from neem and other medicinal plants contain a predominant and insecticidal active ingredient. The application of medicinal plant extracts could be a useful alternative to synthetic chemicals in the postharvest protection and preservation of horticultural crops. This review paper details the application of medicinal plant extracts for postharvest protection and preservation of horticultural crops.