Antimicrobial potential of the Mayan medicine plant Matayba oppositifolia (A. Rich.) Britton against antibiotic-resistant priority pathogens.

ETHNOPHARMACOLOGICAL RELEVANCE: The bark of Matayba oppositifolia (A. Rich.) Britton (commonly known as "huaya" or "palo huacax") is commonly utilized in traditional Mayan medicine for treating diarrhea and for canker and other sores. AIM OF THE STUDY: The aim of this study was to investigate the in-vitro antimicrobial activity of M. oppositifolia bark extracts against drug-susceptible and -resistant ESKAPE-E pathogens. In addition, the phytochemical composition of the best antibacterial extract was analyzed. MATERIALS AND METHODS: The bark extracts were prepared with different solvents, including water, n-hexane, ethyl acetate and methanol. These were tested against ESKAPE-E (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp., including Escherichia coli) strains using Resazurin Microtiter Assay. In addition, the composition of the most active extract was analyzed by GC-MS. RESULTS: The aqueous and organic bark extracts showed activity on drug-susceptible and -resistant ESKAPE-E microbes (MIC = 1000-31.25 µg/mL). The n-hexane bark extract was more active against the superbugs carbapenem-resistant K. pneumoniae (MIC = 500-31.25 µg/mL) and A. baumannii (MIC = 250-125 µg/mL). The GC-MS analysis of this extract allowed the identification of 12 phytochemicals as the potential antibacterial compounds. The major compounds identified were palmitic acid (1), friedelan-3-one (2) and 7-dehydrodiosgenin (3). CONCLUSION: The present study reveals the strong in-vitro antibacterial activity of the n-hexane extract from the bark of M. oppositifolia and demonstrates the potential of natural products as a source of antibacterial compounds or phytomedicines that are specifically effective against drug-resistant ESKAPE-E bugs. Additionally, our investigation contributes to the ethnopharmacological knowledge and reappraisal of Mayan medicinal flora, as well as supports the traditional use of the bark of the medicinal plant M. oppositifolia for the treatment of infectious diseases.

Myrianthus libericus: Possible mechanisms of hypoglycaemic action and in silico prediction of pharmacokinetics and toxicity profile of its bioactive metabolite, friedelan-3-one.

The hypoglycaemic and anti-hyperlipidaemic effects of the 70% ethanol stem bark extract of Myrianthus libericus (MLB), used traditionally in the management of diabetes in Ghana, was evaluated in this study using streptozotocin (45 mg/kg)-induced diabetic rats. In vitro hypoglycaemic activities of the extract and one of its principal compounds, friedelan-3-one were then investigated using α-amylase inhibitory and glucose uptake assay in C2C12 myotubes. In silico analysis of the pharmacokinetic and toxicity properties of the compound was also performed. MLB significantly (p < 0.001) reduced the elevated blood glucose levels and corrected considerably (p < 0.01) the altered serum lipid profiles of the diabetic rats which was comparable to glibenclamide (5 mg/kg). Together with friedelan-3-one, the extract markedly inhibited the activity of α-amylase and promoted glucose uptake in C2C12 cells. Whereas MLB significantly (p < 0.001) up-regulated PI3K and PPARγ transcripts with a corresponding increase in GLUT-4 transcripts within the muscle cells, friedelan-3-one only up-regulated PI3K and GLUT-4 transcripts to promote glucose transport. Friedelan-3-one was shown to be non-carcinogenic, non-hepatotoxic, has decent oral bioavailability and a good compound for optimisation into a drug candidate. The study has demonstrated that MLB possess hypoglycaemic and anti-hyperlipidaemic activities and could be used as a therapeutic agent in the management of diabetes mellitus.