Antimicrobial activity of select edible plants from Odisha, India against food-borne pathogens

Compound isolation through bioassay-guided fractionation of Tectona grandis leaf extract against Vibrio pathogens in shrimp

Tectona grandis Linn, commonly known as teak, is traditionally used to treat a range of diseases, including the common cold, headaches, bronchitis, scabies, diabetes, inflammation, and others. The present study was conducted with the purpose of isolating and identifying the active compounds in T. grandis leaf against a panel of Vibrio spp., which may induce vibriosis in shrimp, using bioassay-guided purification. The antimicrobial activity was assessed using the microdilution method, followed by the brine shrimp lethality assay to determine toxicity. Following an initial screening with a number of different solvents, it was established that the acetone extract was the most effective. The acetone extract was then exposed to silica gel chromatography followed by reversed-phase HPLC and further UHPLC-orbitrap-ion trap mass spectrometry to identify the active compounds. Three compounds called 1-hydroxy-2,6,8-trimethoxy-9,10-anthraquinone, deoxyanserinone B, and khatmiamycin were identified with substantial anti-microbial action against V. parahaemolyticus, V. alginolyticus, V. harveyi, V. anguillarum, and V. vulnificus. The IC50 values of the three compounds viz. 1-hydroxy-2,6,8-trimethoxy-9,10-anthraquinone, deoxyanserinone B, and khatmiamycin varied between 2 and 28, 7 and 38, and 7 and 56 μg/mL, respectively, which are as good as the standard antibiotics such as amoxicillin and others. The in vivo toxicity test revealed that the compounds were non-toxic to shrimp. The results of the study suggest that T. grandis leaf can be used as a source of bioactive compounds to treat Vibrio species in shrimp farming.

Antimicrobial and biocompatibility nature of methanol extract of Lannea coromandelica bark and edible coating film preparation for fruit preservation

This research was performed to evaluate the antimicrobial activity of methanol extract of Lannea coromandelica bark against fruit damage causing microbes such as fungi: Alternaria sp., Aspergillus sp., Botrytis sp., Cladosporium sp., Fusarium sp., Penicillium sp., Phytophthora sp., and Trichoderma sp. The bacteria: such as Chromobacter sp., Enterobacter sp., Erwinia sp., Flavobacterium sp., Lactobacillus sp., Pseudomonas sp., and Xanthomonas sp. was investigated. Furthermore, their biocompatibility nature was determined through animal (rat) model study and their fruit preserving potential was determined by edible coating preparation with chitosan and other substances. Interestingly, the extract showed dose dependent (1000 μg mL-1) activity against these microbes in the following order: Enterobacter sp. (26.4 ± 1.5) > Chromobacter sp. (25.4 ± 1.6) > Pseudomonas sp. (24.5 ± 1.3) > Flavobacterium sp. (24.3 ± 1.4) > Xanthomonas sp. (23.6 ± 1.6) > Erwinia sp. (23.6 ± 1.6) > Lactobacillus sp. (19.6 ± 1.3). Similarly, the antifungal activity was found as Penicillium sp. (32.6 ± 1.3) > Cladosporium sp. (32.6 ± 1.5) > Alternaria sp. (30.3 ± 1.2) > Aspergillus sp. (29.9 ± 1.8) > Botrytis sp. (29.8 ± 1.2) > Fusarium sp. (28.6 ± 1.5) > Trichoderma sp. (19.8 ± 1.4) > Phytophthora sp. (16.2 ± 1.1). The acute toxicity and histopathological study results revealed that the extract possesses biocompatible in nature. The illumination transmittance and active functional groups involved in interaction among test methanol extract and chitosan investigated by UV-vis and Fourier-transform infrared spectroscopy (FTIR) analyses and found average light transmittance and few vital functional groups accountable for optimistic interaction to creak edible coating. Approximately four (set I-IV) treatment sets were prepared, and it was discovered that all of the coated Citrus maxima fruit quality characteristics including total soluble solids (TSS), weight loss (%), pH of fruit pulp juice, and decay percentage were significantly (p>0.05) better than uncoated fruit.

An Overview on Antimicrobial Potential of Edible Terrestrial Plants and Marine Macroalgae Rhodophyta and Chlorophyta Extracts

Antibiotics are used to prevent and treat bacterial infections. After a prolonged use of antibiotics, it may happen that bacteria adapt to their presence, developing antibiotic resistance and bringing up health complications. Nowadays, antibiotic resistance is one of the biggest threats to global health and food security; therefore, scientists have been searching for new classes of antibiotic compounds which naturally express antimicrobial activity. In recent decades, research has been focused on the extraction of plant compounds to treat microbial infections. Plants are potential sources of biological compounds that express several biological functions beneficial for our organism, including antimicrobial activity. The high variety of compounds of natural origin makes it possible to have a great bioavailability of antibacterial molecules to prevent different infections. The antimicrobial activity of marine plants, also called seaweeds or macroalgae, for both Gram-positive and Gram-negative, and several other strains infective for humans, has been proven. The present review presents research focused on the extraction of antimicrobial compounds from red and green macroalgae (domain Eukarya, kingdom Plantae). Nevertheless, further research is needed to verify the action of macroalgae compounds against bacteria in vitro and in vivo, to be involved in the production of safe and novel antibiotics.

Biological activities of different plant species belonging to the Asteraceae family

Achillea biebersteinii and Anthemis tinctoria, which are widely distributed species of the Asteraceae family, are used in folk medicine in the form of herbal tea or extract in the treatment of many diseases. The aim of this study was to investigate the chemical content, antimicrobial, antioxidant, enzyme inhibitor activities and cytotoxic effects of 80% ethanol extract of these two species and make a comparative analysis. In accordance with the data obtained, the major component of A. biebersteinii was determined as Cyclododecane (14.47%), while that of A. tinctoria was determined as Phytol (23.15%). A. biebersteinii, which showed moderate activity in terms of antimicrobial activity, produced more active inhibition than A. tinctoria did. Both plants showed high levels of antioxidant activity. The total phenol and total flavonoid contents of A. tinctoria were higher than those of A. biebersteinii. It was determined that there was no significant activity when the extracts were compared with galanthamine, which is the reference drug in terms of enzyme inhibitory activity. When the in vitro anticancer activity of human breast cancer cell line was examined, it was determined that A. tinctoria had a cytotoxic effect at high concentrations (IC50;0.82mg/mL), and A. biebersteinii showed strong cytotoxicity at all concentrations (IC50;<0.0625mg/mL). These two plants of the same family were evaluated in terms of many different biological parameters and it was revealed that A. biebersteinii was more active than A. tinctoria. However, in vivo studies are needed to determine whether these plants can be used as phytotherapeutic agents.

Pharmacological and phytochemical potential of Rubus ellipticus: a wild edible with multiple health benefits

OBJECTIVES

Rubus ellipticus (family Rosaceae) is used for its delicious edible fruits in the Himalayan region and other parts of the globe. However, the full potential of the species is yet to be harnessed. The current review focuses on the phytochemical, traditional uses, morphological, molecular and pharmacological potential of R. ellipticus.

KEY FINDINGS

The review of the literature reveals that many health-promoting compounds of R. ellipticus have been reported from the species along with the different biological properties, such as nephroprotective, anti-inflammatory, analgesic, anti-pyretic, anti-proliferative, cytotoxicity, anti-cancer, wound healing, anti-fertility, anti-plasmodial, anti-microbial and antioxidant. Traditionally, it is used in many formulations, which are validated through primary pharmacological assays. However, several medicinal properties are still need to be validated through detailed pharmacological and clinical studies.

SUMMARY

All the information is available in a scanty form, and the complete information is missing on a single platform. Such type of information will help researchers to better utilize the available data for initiating future research on the species as it has the potential to contribute to the food and pharmaceutical industry. The review highlights the need for further studies on the species to harness its potential in nutraceutical, functional food, energy supplement, and beneficial therapeutic drug development program.

Variation of phytochemical constituents, antioxidant, antibacterial, antifungal, and anti-inflammatory properties of Grantia aucheri (Boiss.) at different growth stages

Phyto-natural products are deeply associated with ethno-medicinal practices with less or more scientific validation for curing many vital diseases. Thus, the present study was carried out to asses chemical constituents and bioactivities of Grantia aucheri Boiss at different growth stages (vegetative, flowering, and seeding). For this aim, the chemical composition of G. aucheri ethanolic extracts was analyzed by gas chromatography with mass spectrometry detection (GC-MS), their total phenolics, total flavonoids, total tannins, and total anthocyanins concentrations were also spectrophotometrically determined. Antifungal and antibacterial activities were determined against three pathogenic fungi and six human pathogenic bacteria. Furthermore, antioxidant activity (DPPH and ABTS scavenging) and anti-inflammatory activity (Human Red Blood Cell Stabilization Method) were evaluated. The highest content of total phenolics, total flavonoids, total tannins, and total anthocyanins were established in the extract of G. aucheri at its flowering stage. Such phyto-compounds as boranyl acetate, β-himachalene and himachalol were major compounds found among 34 chemical constituents identified. The best antioxidant, anti-inflammatory, antifungal, and antibacterial activities were also found for this extract. Its phytochemicals presented bactericidal activities, mainly against Staphylococcus aureus, Bacillus subtilis, and Streptococcus pyogenes along with moderate fungicidal activity, however, it was less effective than the first one. Apart from antioxidant, antimicrobial, and anti-inflammatory activities, chemical constituents of G. aucheri may be potential alternative biomedical applications to reduce synthetic chemicals drugs.

Ethnobotanical study of Hakka traditional medicine in Ganzhou, China and their antibacterial, antifungal, and cytotoxic assessments

Background

Traditional herbs played a crucial role in the health care of the Hakka people. However, studies to identify these traditional herbs are few. Here we document and assess the potential of these plants for treating microbial infections. Many herbs used by the Hakka people could potentially be a novel medicinal resource.

Methods

Local herb markets were surveyed via semi-structured interviews, complemented by direct observations to obtain information on herbal usage. For each herb selected for this study, extracts in four different solvents were prepared, and tested for activity against 20 microorganisms, as well as cancerous and noncancerous cells. All data were subjected to cluster analysis to discover relationships among herbs, plant types, administration forms, solvents, microorganisms, cells, etc., with the aim to discern promising herbs for medicine.

Results

Ninety-seven Hakka herbs in Ganzhou were documented from 93 plants in 62 families; most are used for bathing (97%), or as food, such as tea (32%), soup (12%), etc. Compared with the Chinese Pharmacopoeia and Chinese Materia Medica, 24 Hakka medicines use different plant parts, and 5 plants are recorded here for the first time as traditional medicines. The plant parts used were closely related with the life cycle: annual and perennial herbs were normally used as a whole plant, and woody plants as (tender) stem and leaf, indicating a trend to use the parts that are easily collected. Encouragingly, 311 extracts (94%) were active against one or more microorganisms. Most herbs were active against Gram-positive bacteria, such as Staphylococcus aureus (67%), Listeria innocua (64%), etc. Cytotoxicity was often observed against a tumor cell, but rarely against normal cells. Considering both antimicrobial activity and cytotoxicity, many herbs reported in this study show promise as medicine.

Conclusion

Hakka people commonly use easily-collected plant parts (aerial parts or entire herb) as medicine. External use of decoctions dominated, and may help combating microbial infections. The results offer promising perspectives for further research since little phytopharmacology and phytochemistry has been published to date.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03712-z.

Exploration of Lamiaceae in Cardio Vascular Diseases and Functional Foods: Medicine as Food and Food as Medicine

In the current scenario, cardiovascular disease (CVD) is one of the most life-threatening diseases that has caused high mortality worldwide. Several scientists, researchers, and doctors are now resorting to medicinal plants and their metabolites for the treatment of different diseases, including CVD. The present review focuses on one such family of medicinal plants, called Lamiaceae, which has relieving and preventive action on CVD. Lamiaceae has a cosmopolitan distribution and has great importance in the traditional system of medicine. Lamiaceae members exhibit a wide range of activities like antioxidant, antihyperlipidemic, vasorelaxant, and thrombolytic effect, both in vitro and in vivo–these are mechanisms that contribute to different aspects of CVD including stroke, heart attack, and others. These plants harbour an array of bioactive compounds like phenolic acids, flavonoids, alkaloids, and other phytochemicals responsible for these actions. The review also highlights that these plants are a rich source of essential nutrients and minerals like omega-3 and hence, can serve as essential sources of functional foods—this can have an additional role in the prevention of CVDs. However, limitations still exist, and extensive research needs to be conducted on the Lamiaceae family in the quest to develop new and effective plant-based drugs and functional foods that can be used to treat and prevent cardiovascular diseases worldwide.

Phytochemical analysis, antioxidant, cytotoxic, and antimicrobial activities of golden chamomile (Matricaria aurea (Loefl.) Schultz Bip)

Matricaria aurea (Loefl.) Schultz Bip. (Asteraceae), known as golden chamomile, has been traditionally used for the treatment of various diseases. In this study, total phenolic, flavonoid, and tannin contents of total extract and different fractions of this plant were determined. The antioxidant, cytotoxic, and antimicrobial activities were also evaluated. Moreover, the phenolic profiles of selected fractions were determined by HPLC and LC-MS/MS analysis. Results demonstrated total phenolic contents of 37.8-57.2 mg GAE/g and total flavonoid contents of 3.0-111.2 mg QE/g. The ethyl acetate and methanol fractions (EF and MF) had the highest concentrations of phenolic, tannin, and flavonoid compounds. In both DPPH radical scavenging assay and phosphomolybdenum reduction assay, EF showed the best antioxidant activity, followed by MF. EF and MF indicated also the best antibacterial activities against Bacillus subtilis (MIC 1.56 and 12.5 mg ml^-1) and Staphylococcus aureus (MIC 0.78 and 12.5 mg ml^-1). Hexane fraction (HF) had no antibacterial effect. None of the samples had antifungal effect. MTT (3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay revealed for EF and HF the highest antiproliferative activities (IC₅₀ values ranged from 111.8 to 294.6 μg ml^-1). The presence of chlorogenic acid, ferulic acid, and luteolin-7-O-glucoside in MF, and p-coumaric acid in EF was confirmed and quantified.

Exploring Dose-Dependent Cytotoxicity Profile of Gracilaria edulis-Mediated Green Synthesized Silver Nanoparticles against MDA-MB-231 Breast Carcinoma

Green-based synthesis of metal nanoparticles using marine seaweeds is a rapidly growing technology that is finding a variety of new applications. In the present study, the aqueous extract of a marine seaweed, Gracilaria edulis, was employed for the synthesis of metallic nanoparticles without using any reducing and stabilizing chemical agents. The visual color change and validation through UV-Vis spectroscopy provided an initial confirmation regarding the Gracilaria edulis-mediated green synthesized silver nanoparticles. The dynamic light scattering studies and high-resolution transmission electron microscopy pictographs exhibited that the synthesized Gracilaria edulis-derived silver nanoparticles were roughly spherical in shape having an average size of 62.72 ± 0.25 nm and surface zeta potential of -15.6 ± 6.73 mV. The structural motifs and chemically functional groups associated with the Gracilaria edulis-derived silver nanoparticles were observed through X-ray diffraction and attenuated total reflectance Fourier transform infrared spectroscopy. Further, the synthesized nanoparticles were further screened for their antioxidant properties through DPPH, hydroxyl radical, ABTS, and nitric oxide radical scavenging assays. The phycosynthesized nanoparticles exhibited dose-dependent cytotoxicity against MDA-MB-231 breast carcinoma cells having IC50 value of 344.27 ± 2.56 μg/mL. Additionally, the nanoparticles also exhibited zone of inhibition against pathogenic strains of Bacillus licheniformis (MTCC 7425), Salmonella typhimurium (MTCC 3216), Vibrio cholerae (MTCC 3904), Escherichia coli (MTCC 1098), Staphylococcus epidermidis (MTCC 3615), and Shigella dysenteriae (MTCC9543). Hence, this investigation explores the reducing and stabilizing capabilities of marine sea weed Gracilaria edulis for synthesizing silver nanoparticles in a cost-effective approach with potential anticancer and antimicrobial activity. The nanoparticles synthesized through green method may be explored for their potential utility in food preservative film industry, biomedical, and pharmaceutical industries.

Leaf Extract and Active Fractions of Dillenia pentagyna Roxb. Reduce In Vitro Human Cancer Cell Migration Via NF-κB Pathway

Background:

Different parts of Dillenia pentagyna have long been used in traditional medicines to cure several diseases including cancer. However, the mechanism(s) of anti-cancer effects are still unknown. We aimed to elucidate the anti-metastatic potential of ethanolic extracts of leaves of D. pentagyna (EELDP) and active fractions of it in highly metastatic human cancer cells.

Methods:

We screened different HPLC fractions of EELDP based on their anti-metastatic effect. We used TLC and ESI-MS for determining the presence of various phytochemicals in EELDP and fractions. We monitored in vitro anti-metastasis effect of EELDP (0-0.6 mg/ml) and active fractions (0-0.050 mg/ml) on various human cancer cells like A549, HeLa, and U2OS.

Results:

EELDP significantly reduced cell viability and cell migration in A549, HeLa, and U2OS cells. However, higher sensitivity was observed in A549 cells. We screened 2 active HPLC fractions F6 and F8 having anti-MMPs activity. EELDP and active fractions reduced metastasis via the NF-κB pathway, decreased the expression of Vimentin, N-cadherin, and increased the expression of Claudin-1.

Conclusion:

Significant reduction of metastasis by EELDP at a dose of 0.1 mg/ml or by active fractions at 0.050 mg/ml implicates that the active compound(s) present in crude or fractions are extremely potent to control highly metastatic cancer.

Phytochemical analysis, antioxidant, antibacterial, and cytotoxic activities of leaves and roots of Rubus hyrcanus Juz

Rubus hyrcanus Juz. (Rosaceae), known as Caspian blackberry, is wildly distributed around the Caspian Sea. This study focused on antioxidant, cytotoxic, and antibacterial activities of total extracts and different fractions from the roots and leaves of this species. The total phenolics and flavonoid contents were also evaluated. Finally, the phenolic profiles of selected fractions were determined using HPLC–DAD and LC–MS/MS. The results indicated that the total phenolics content (TPC) of root total extract (RTE) was 3.5 times that of leaves (340.4 and 102.7 mg GAE/g, respectively). The TPC of three root fractions ranged from 226.6 to 392.9 mg GAE/g, while in leaves fractions, it ranged between 68.3 and 101.8 mg GAE/g. The total extract of leaves had higher contents of total flavonoids than roots (70.5 and 8.9 mg QE/g, respectively). The methanol fractions of both parts had the highest amounts of flavonoids. The root methanol fraction (RMF) had the best antioxidant effect in both DPPH radical scavenging assay (IC50: 9.16 μg ml−1) and total antioxidant capacity test (1010.5 mg ɑTE/g). The RMF and RTE had potent antibacterial activities against Bacillus subtilis and Staphylococcus aureus (MIC 1.5 mg ml−1). In the MTT assay, ethyl acetate fractions of roots and leaves exhibited the best cytotoxicity (IC50 247 and 227 μg ml−1, respectively) and the highest selectivity indexes (4.73 and 5.31, respectively). Phytochemical analysis revealed the presence of gallic acid, p-coumaric acid, and chlorogenic acid in leaves ethyl acetate fraction, chlorogenic acid in leaves methanol fraction, and gallic acid in the root ethyl acetate fraction.

Bioassay-guided isolation of antibacterial compounds from the leaves of Tetradenia riparia with potential bactericidal effects on food-borne pathogens

ETHNOPHARMACOLOGICAL RELEVANCE

Tetradenia riparia (commonly known as ginger bush) is frequently used in traditional African medicine to treat foodborne infections including diarrhoea, gastroenteritis, and stomach ache.

AIM OF THE STUDY

The present study aims to identify in Tetradenia riparia the compounds active against foodborne pathogens.

MATERIALS AND METHODS

Dried Tetradenia riparia leaf powder was consecutively extracted with hexane, ethyl acetate, methanol and water. The hexane extract was counter-extracted with methanol:water (9:1), and after evaporation of the methanol, this phase was extracted with dichloromethane. The water extract was counter-extracted with butanol. All these fractions were tested against a panel of foodborne bacterial pathogens. A bioassay-guided purification was performed to isolate antimicrobial compounds using Staphylococcus aureus as a target organism. Further, antibiofilm activity was evaluated on S. aureus USA 300.

RESULTS

The dichloromethane fraction and ethyl acetate extract were the most potent, and therefore subjected to silica gel chromatography. From the dichloromethane fraction, one active compound was crystalized and identified using NMR as 8(14),15-sandaracopimaradiene-7alpha, 18-diol (compound 1). Two active compounds were isolated from the ethyl acetate extract: deacetylumuravumbolide (compound 2) and umuravumbolide (compound 3). Using a microdilution method, their antimicrobial activity was tested against eight foodborne bacterial pathogens: Shigella sonnei, S. flexneri, Salmonella enterica subsp. enterica, Escherichia coli, Micrococcus luteus, S. aureus, Enterococcus faecalis, and Listeria innocua. Compound 1 had the strongest activity (IC₅₀ ranging from 11.2 to 212.5 μg/mL), and compounds 2 and 3 showed moderate activity (IC₅₀ from 212.9 to 637.7 μg/mL and from 176.1 to 521.4 μg/mL, respectively). Interestingly, 8(14),15-sandaracopimaradiene-7alpha, 18-diol is bactericidal, and also showed good antibiofilm activity with BIC₅₀ (8.8 ± 1.5 μg/mL) slightly lower than for planktonic cells (11.4 ± 2.8 μg/mL).

CONCLUSIONS

These results support the traditional use of this plant to conserve foodstuffs and to treat gastrointestinal ailments, and open perspectives for its use in the prevention and treatment of foodborne diseases.

Nematicidal Activity of Holigarna caustica (Dennst.) Oken Fruit Is Due to Linoleic Acid

Holigarna caustica (Dennst.) Oken is used by the tribes of Northeast India for the treatment of intestinal problems. Therefore, the present study was undertaken to investigate the active principles of this plant responsible for its anthelmintic activity, using bioassay-guided fractionation. An ethanol extract of H. caustica fruit was fractionated on a silica gel column, followed by HPLC, while nematicidal activity was followed throughout on Caenorhabditis (C.) elegans as a model organism. Our study constitutes the first nematicidal report for this plant. Bioassay-guided purification led to the isolation of one compound (IC₅₀ = 0.4 µM) as the only active constituent in the most active fraction. The compound was identified as linoleic acid based on spectroscopic data (¹H and ¹³C NMR and ESI-MS). No cytotoxicity was observed in the crude extract or in linoleic acid (up to 356 µM). The results support the use of H. caustica for the treatment of intestinal problems by traditional healers in India.

Antiviral and Cytotoxic Activity of Different Plant Parts of Banana (Musa spp.)

Chikungunya and yellow fever virus cause vector-borne viral diseases in humans. There is currently no specific antiviral drug for either of these diseases. Banana plants are used in traditional medicine for treating viral diseases such as measles and chickenpox. Therefore, we tested selected banana cultivars for their antiviral but also cytotoxic properties. Different parts such as leaf, pseudostem and corm, collected separately and extracted with four different solvents (hexane, acetone, ethanol, and water), were tested for in vitro antiviral activity against Chikungunya virus (CHIKV), enterovirus 71 (EV71), and yellow fever virus (YFV). Extracts prepared with acetone and ethanol from leaf parts of several cultivars exhibited strong (EC₅₀ around 10 μg/mL) anti-CHIKV activity. Interestingly, none of the banana plant extracts (concentration 1–100 µg/mL) were active against EV71. Activity against YFV was restricted to two cultivars: Namwa Khom–Pseudostem–Ethanol (5.9 ± 5.4), Namwa Khom–Corm–Ethanol (0.79 ± 0.1) and Fougamou–Corm–Acetone (2.5 ± 1.5). In most cases, the cytotoxic activity of the extracts was generally 5- to 10-fold lower than the antiviral activity, suggesting a reasonable therapeutic window.

Antibacterial, Antifungal, Antiviral, and Anthelmintic Activities of Medicinal Plants of Nepal Selected Based on Ethnobotanical Evidence

Background

Infections by microbes (viruses, bacteria, and fungi) and parasites can cause serious diseases in both humans and animals. Heavy use of antimicrobials has created selective pressure and caused resistance to currently available antibiotics, hence the need for finding new and better antibiotics. Natural products, especially from plants, are known for their medicinal properties, including antimicrobial and anthelmintic activities. Geoclimatic variation, together with diversity in ethnomedicinal traditions, has made the Himalayas of Nepal an invaluable repository of traditional medicinal plants. We studied antiviral, antibacterial, antifungal, and anthelmintic activities of medicinal plants, selected based upon ethnobotanical evidence.

Methods

Ethanolic and methanolic extracts were tested (1) on a panel of microbes: two Gram-positive bacteria (Staphylococcus aureus and Listeria innocua), four Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica, and Shigella sonnei), and one fungal species: Candida albicans; (2) against three different viruses: yellow fever, chikungunya, and enterovirus; and (3) on the nematode Caenorhabditis elegans. Also, cytotoxicity was assessed on human hepatoma (Huh), rhabdosarcoma (RD), and Vero (VC) cell lines.

Results

Of 18 plants studied, Ampelocissus tomentosa and Aleuritopteris anceps inhibited S. aureus (MIC 35 μg/mL and 649 μg/mL, respectively) and Pseudomonas aeruginosa (MIC 15 μg/mL and 38 μg/mL, respectively). Rhododendron arboreum and Adhatoda vasica inhibited S. enterica (MIC 285 μg/mL and 326 μg/mL, respectively). Kalanchoe pinnata, Ampelocissus tomentosa, and Paris polyphylla were active against chikungunya virus, and Clerodendrum serratum was active against yellow fever virus (EC₅₀ 15.9 μg/mL); Terminalia chebula was active against enterovirus (EC₅₀ 10.6 μg/mL). Ampelocissus tomentosa, Boenninghausenia albiflora, Dichrocephala integrifolia, and Kalanchoe pinnata significantly reduced C. elegans motility, comparable to levamisole.

Conclusions

In countries like Nepal, with a high burden of infectious and parasitic diseases, and a current health system unable to combat the burden of diseases, evaluation of local plants as a treatment or potential source of drugs can help expand treatment options. Screening plants against a broad range of pathogens (bacteria, viruses, fungi, and parasites) will support bioprospecting in Nepal, which may eventually lead to new drug development.

Antimicrobial Activity of Selected Banana Cultivars Against Important Human Pathogens, Including Candida Biofilm

Ten banana (Musa spp.) cultivars were studied for their antimicrobial properties. Three plant parts (corm, pseudostem and leaves) were collected separately and extracted with different solvents, viz., hexane, acetone, ethanol and water. The 50% inhibitory concentration (IC₅₀) was evaluated using a broth microdilution assay. Eight human bacterial and one fungal pathogen were tested. Acetone and ethanol extract(s) often exhibited significant antimicrobial activity, while hexane extracts were less active. Aqueous extracts often showed microbial growth, possibly by endophytes. Leaf extracts were most active, followed by pseudostem, and corm was least active. All the tested banana cultivars were found to contain antimicrobials, as demonstrated by inhibition of selected human pathogens. However, cultivars such as Dole, Saba, Fougamou, Namwah Khom, Pelipita and Mbwazirume showed a broad-spectrum activity, inhibiting all tested pathogens. Other cultivars such as Petit Naine and Kluai Tiparot showed a narrow-spectrum activity, including antibiofilm activity against Candida albicans. Our results support the use of different parts of banana plants in traditional human medicine for infections, including diarrhea and dysentery, and some sexually transmitted diseases, as well as for packaging spoilable materials like food.