ABSTRACT

Buccholzia coriacea commonly called wonderful kola has been used in traditional medicine to treat hypertension, headache, and infectious diseases among others. The objectives of this research was to isolate and characterize secondary metabolites from the stem bark of Buchholzia coriacea, as well as to investigate the phytochemical content, antioxidant capacity and antimicrobial activity of the plant material. Stem bark of the plant material was subjected to cold maceration in ethanol and the crude extract was partitioned between chloroform and n-hexane(1:1). Column chromatography and thin layer chromatography (TLC) were employed to purify the chloroform extract. The proposed structures were elucidated using a combination of infra-red spectroscopy (IR), ¹HNMR and ¹³CNMR, DEPT, COSY, HSQC, HMBC, mass spectrometry (Q-Tof MS ES⁺). Two new compounds were proposed as: a glycoside named as (2Z, 4Z, 6E)-(tetrahydro-2,3,5,6-tetramethoxy-2H-pyran-2yl)methoxy)-17-(1,3-dioxan-5-yl)-21-hydroxy-8(hydroxymethyl)-9-methlyhenicosa-2,4,6-trien-11-one,  with molecular formular C₃₇H₆₄O₁₁, showing   a molecular ion (M⁺) peak at 685, a white crystalline solid with R_f 0.86 in n-hexane/chloroform/methanol (40:30:30); a steroid amidonitrile tetraene, named as cyano-N- (12E, 14E, 18Z)-19-(hexadecahydro-10,13-dimethyl-1H-cyclopenta[α]phenanthren-17-yl)nonadeca-12,14,16,18-tetraenylformamide, with molecular formula C₄₀H₆₂N₂O  and molecular mass of  586, a golden yellow oil, with R_f 0.62 in n-hexane/chloroform/methanol (25:15:60). Phytochemical analysis which was carried using standard methods, showed that the tannins content of 0.931% constitute the highest amount of phytochemicals present. The plant sample exhibited exceptional antioxidant capacity and good antimicrobial activity. The Zone Diameter of Inhibition of the bacteria and fungi by the methanol, chloroform and n-hexane extracts were compared with clinical standards.  The clinical standards used were chloramphenicol for the bacteria, and nystatin for the fungi. Minimum Inhibitory Concentration (MIC) of the chloroform extracts was 200 mg/ml against the bacteria and from 100mg/ml to >250 mg/ml against the tested fungi. The results from this study lend credence to the use of wonderful kola in traditional medicine and give scientific evidence for the potentiality of using chemical agents from Buchholzia coriacea in the treatment of infectious and degenerative diseases.