GC-MS Profile, Spectrophotometric Determination of Antioxidant Activity, Total Phenolic and Flavonoid Contents of Leaves of Cochlospermum Planchonii

Abstract

ABSTRACT <em>Cochlospermum planchonii</em> is a multipurpose traditional medicinal plant that is found in most tropical regions of the world. The objectives of this research were to identify the class and type of phytochemicals present, quantify the total phenolic and flavonoid contents, and determine the antibacterial and antioxidant activity of the plant leaves extract. This was achieved by extracting with two solvents of very different polarity (n-hexane and methanol). Harborne’s method was used for the identification of the class of phytochemicals while GC-MS was used to identify the type of phytochemicals. Folin-Ciocalteau method was used to determine the total phenolic content while aluminum colorimetric assay was used to determine the total flavonoid content. Kirby-Bauer disc diffusion method was used for the antibacterial assay while DPPH was used to evaluate the antioxidant activity. The phytochemical screening showed presence of flavonoids, saponins, tannins, terpenoids and glycosides while terpenoids, alkaloids and anthraquinones were absent in the methanol extract. Steroids and terpenoids were present in the n-hexane extract while saponins, alkaloids, anthraquinones and glycosides were absent. The total phenolic and flavonoid contents obtained were 97.48 ± 0.42 mg Gallic acid equivalent/g extract and 161.85 ± 0.37 mg quercetin equivalent/ g extract respectively. Several phytochemicals were identified using GC-MS. The most abundant in the methanol and n-hexane extracts was n-hexadecanoic acid (9.90%) and octacosane (24.24%) respectively. The observed DPPH scavenging activity was 66.73 ± 0.26% while extract reduced Fe³⁺ ferricyanide complex to the ferrous form (Fe²⁺). The methanol extract was active against <em>Staphylococcus aureus</em>, <em>Salmonella typii</em>, <em>Streptococcus pyogenes</em>, <em>Proteus mirabilis</em> and <em>Pseudomonas aeruginosa</em>. The leaves of <em>Cochlospermum planchonii</em> is rich in phenolics and flavonoids and possess high antioxidant activity. It also exhibits antibacterial activity against some human pathogens. <strong>Keywords:</strong> <em>Cochlospermum planchonii</em>, Phenolics, flavonoids, Antioxidant, antibacterial, GC-MS