HPLC Analysis and Antimicrobial Screening of Methanol Extract/Fractions of the Root of Millettia aboensis (Hook.f.) Baker against Streptococcus mutans

Millettia aboensis (Hook.f.) Baker belongs to the Leguminosae family, known locally as nduezi in Igbo, erurumesi in Edo, and Òdúdū in Efik. The plant parts have proven to be active against some diseases. The plant was studied for its antimicrobial activity and the phytochemicals present. The plant materials were macerated and fractionated using different extraction methods. The compounds present in the fractions of the stem were detected with the aid of HPLC-DAD. The efficacy of the crude methanol and fractions from the root part was evaluated against Streptococcus mutans. The results showed that the aqueous fraction extract had the highest percentage yield (51.11%), followed by the ethyl acetate (24.10%), butanol (6.63%), and hexane (5.56%), while the methanol extract had a yield of 2.48%. Nine phytochemical compounds were detected from the fractions of the root extract: bis-oxazolidinone derivative – 1, circumdatin F – 2, enniatin B – 3, septicine – 4, orobol 8-C-glucoside – 5, rocaglamide – 6, genistein 6-C-glucoside – 7, 3-phenyl chromen-4-one – 8, and corynesidone D – 9. The methanol extract/fractions of M. aboensis showed no antimicrobial activities on clinical isolates at different concentrations (6.25-50 mg/ml). Based on the poor activity against Strep. mutans, but with promising phytoconstituents present, the extract/fractions need further investigation as regards its utilization against other pathogens.