Abstract

Pavetta crassipes leaf (Fam. Rubiaceae) is used as part of a combination herbal remedy for the treatment of
tuberculosis (TB) and other respiratory infections in Nigerian ethno medicine. However, little scientific data is
available to support the use in ethnomedical therapy so the objective of the study was to assess the antitubercular property and to identify the bioactive components. The dried powdered leaf was sequentially
extracted with solvents to obtain hexane, dichloromethane, methanol and water extracts. Following which, the
extracts were then screened against Mycobacterium aurum, a rapidly growing saprophytic mycobacterium
species for activity. The methanol extract exhibited inhibitory activity at an MIC value of 250 µg/mL against M.
aurum and two known polyphenolic compounds were isolated as 5-O-caffeoylquinic acid methyl ester and
quercetin-3-rutinoside (rutin). Reversed phase semi-preparative HPLC, mass spectrometry and 1H and 13C
NMR techniques were utilized in isolating and characterizing the two components. The assignments of the
structures were consistent with data from the literature. The study has shown that the methanol extract has some
activity and hyphenation of LC-MS can be used for the isolation of polyphenols from the methanol fraction
without a rigorous purification process.