Selemani, M. A. | Search bioRxiv

bioRxiv2022

Antidiabetic, antioxidant and in silico molecular docking of Xeroderris stuhlmannii (Taub.) Mendonca & E.P. Sousa phytochemical compounds on human pancreatic α-amylase and human lysosomal acid-α-glucosidase

Ethnopharmacological relevanceHerbal traditional medicine is used by millions of people in Africa for treatment of ailments such as diabetes mellitus, stomach disorders and respiratory diseases. Xeroderris stuhlmannii (Taub.) Mendonca & E.P. Sousa (X. stuhlmannii (Taub.)) is a medicinal plant used traditionally in Zimbabwe to treat type 2 diabetes mellitus (T2DM) and its complications. However, there is no scientific evidence to support its inhibitory effect against digestive enzymes (-glucosidases) that are linked to high blood sugar in humans. Aim of the study: This work aims to investigate whether bioactive phytochemicals of crude X. stuhlmannii (Taub.) can scavenge free radicals and inhibit -glucosidases in order to reduce blood sugar in humans. Materials and methodsHere we examined the free radical scavenging potential of crude aqueous, ethyl acetate and methanolic extracts of X. stuhlmannii (Taub.) using the diphenyl-2-picrylhydrazyl assay in vitro. Furthermore, we carried out in vitro inhibition of -glucosidases (-amylase and -glucosidase) by the crude extracts using chromogenic 3,5-dinitrosalicylic acid and p-nitrophenyl--D-glucopyranoside substrates. We also used molecular docking approaches (Autodock Vina) to screen for bioactive phytochemical compounds targeting the digestive enzymes. ResultsOur results showed that phytochemicals in X. stuhlmannii (Taub.) aqueous, ethyl acetate and methanolic extracts scavenged free radicals with IC50 values ranging from 0.002-0.013 g/mL. Furthermore, crude aqueous, ethyl acetate and methanolic extracts significantly inhibited -amylase and -glucosidase with IC50 values of 10.5-29.5 g/mL (versus 54.1{+/-}0.7 g/mL for acarbose) and 8.8-49.5 g/mL (versus 161.4{+/-}1.8 g/mL for acarbose), respectively. In silico molecular docking findings and pharmacokinetic predictions showed that myricetin is likely a novel plant-derived -glucosidase inhibitor. ConclusionCollectively, our findings suggest pharmacological targeting of digestive enzymes by X. stuhlmannii (Taub.) crude extracts may reduce blood sugar in humans with T2DM via inhibition of -glucosidases.

plant biology↗

bioRxiv2020

Phytochemical characterization and in vitro antibacterial activity of Xeroderris stuhlmannii (Taub.) Mendonca & E.P. Sousa bark extracts

The use of herbal medicine is common in many rural communities in Zimbabwe because generic drugs are expensive and not readily available. In this work, we documented the important phytochemicals from Xeroderris stuhlmannii (Taub.) Mendonca & E.P. Sousa (Murumanyama in Shona), bark extracts and tested their antibacterial activity in order to demonstrate its potential as an antimicrobial agent. Qualitative screening of secondary metabolites confirmed the presence of alkaloids, flavonoids, terpenoids, steroids and polyphenols in the crude bark extracts. The MICs values for the crude extracts on six bacterial strains ranged from 0.23-0.80 mg/mL. Antimicrobial tests showed higher potency for crude bark extracts on E. Coli (MIC, 0.232 mg/mL) and lower potency on coliform (MIC, 0.798 mg/mL). LC-MS/MS analysis of various fractions confirmed the presence of twenty-eight phytochemicals whereas, twelve phytochemicals were identified using GC-MS. Both techniques confirmed the presence of ursolic acid, roburic acid, reticuline, rotenone and p-coumaric acid glucoside in hexane and methanol extracts. In summary, our findings show that Xeroderris stuhlmannii (Taub.) Mendonca & E.P. Sousa contain many phytochemical compounds that have antimicrobial activity. Moreover, some of the compounds in the bark extract have been shown to possess antioxidant, antiviral, antitumor and anti-inflammatory properties. Thus, Xeroderris stuhlmannii (Taub.) Mendonca & E.P. Sousa barks can act as a useful herbal supplement for treatment of a number of diseases in rural communities where modern drugs are expensive and not readily available.

plant biology↗