Abstract

Ofentse Mazimba *, Runner R. T. Majinda and Daniel Motlhanka

The objective of this study was to isolate and characterize the constituents of the local Morus nigra L. (Black mulberry), to compare its constituents with other studied Mulberries and to evaluate its anti-oxidative and antibacterial activities. The isolated compounds were identified by comparison of spectral data (UV, IR, MS and NMR) with literature values. The stem bark and wood of M. nigra yielded a stilbenoid oxyresveratrol 1, a 2- arylbenzofuran moracin M2, four isoprenylated flavonoids; cyclomorusin 3, morusin 4, kuwanon C5 and a derivative of kuwanon C6, two tritepenes; betulinic acid 7, -amyrin acetate 8 and a steroidal saponin -sitosterol-3-O- -D- glucoside 9. The phenolic isolates showed moderate DPPH radical scavenging activity (EC50 = 23-135 µgml-1 ) compared to ascorbic acid (EC50 = 41 µgml-1 ) after 30 min. Compounds 1, 2 and 4 to 6 showed activities against Staphylococcus aureus, Bacillus subtilis, Micrococus flavus, Streptococcus faecalis, Salmonella abony, Pseudomonas aeruginosa.