OBJECTIVEThis study evaluates the phytochemical constituents, antioxidant and anti-inflammatory activity, cytotoxicity, and inhibitory activity against carbohydrate metabolism of extracts from Ocotea bullata stem bark.

METHODSHexane, ethyl acetate, methanol and water were used to extract the air-dried sample. The phytochemical investigation and antioxidant assays were carried out on the extracts using standard procedures. The antidiabetic and anti-inflammatory potentials were evaluated using α-amylase, α-glucosidase and 5-lipoxygenase enzymes respectively. Vero cells were employed to determine the cytotoxicity of the extracts.

RESULTSThe ethyl acetate extract showed higher phenolic contents (8.97 mg/g gallic acid) while methanol displayed higher flavonoid (36.06 mg/g quercetin) and flavonol (153.44 mg/g rutin) contents than other extracts. Hexane extract had the greatest capacity to scavenge 1,1-diphenyl-2-picryl-hydrazyl (0.19 mg/mL), hydroxyl (25.77 mg/mL) and 2,2-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid (0.07 mg/mL) radicals, while ethyl acetate extract exhibited stronger inhibition (P < 0.05) against superoxide anion (0.41 mg/mL) and ferric ion-reducing power (2.36 mg/mL) compared to other extracts and standards. Aqueous extract (27.02 mg/mL) exhibited strong metal-chelating activity (P < 0.05) compared to other extracts and gallic acid. The aqueous extract demonstrated the greatest inhibition of α-glucosidase (1.45 mg/mL) and α-amylase (2.43 mg/mL) compared to other extracts and acarbose. There were no significant differences (P < 0.05) in half-maximum inhibitory concentration (IC) values of all tested extracts and indomethacin in the inhibition of 5-lipoxygenase activity. The aqueous extract was nontoxic to Vero cells with an ICvalue of 0.38 mg/mL.

CONCLUSIONO. bullata stem bark contains active phytochemicals with diverse pharmacological potentials that could be beneficial in managing diabetes and inflammation.

Objectives To investigate antimicrobial and cytotoxic potentials as well as chemical constituents of extracts from Macaranga barteri (M. barteri). Methods Antimicrobial activity was carried out using micro-dilution, cell culture and GC–MS methods were employed to determine the cytotoxicity and chemical constituents of the extracts respectively. Results Marked activity was observed in methanol (ME) fraction [MIC