Phytochemical Profiling and Pharmacognostic Evaluation of Oldenlandia corymbosa and Ocimum sanctum Leaves Hydroalcoholic Extracts: Comparative Study

Abstract

Herbs are an important source of bioactive substances. These are widely used to treat several disorders for better function in the human body, minimum toxic effects, and widespread availability. A total of two medicinal herbs from West Bengal, India, such as Oldenlandia corymbosa (Diamond flower) and Ocimum sanctum (Holy basil), are being considered for inclusion in the current study. Hydroalcoholic extracts (70% ethanolic) of the two plants' leaves were analyzed to detect and quantify important phytochemical substances and investigate in vitro antioxidant and pharmacological effects. Spectrophotometric and HPLC-DAD techniques were used for the quantitative estimation of different phytochemicals. In addition, in vitro antimicrobial properties were studied using the Kirby-Bauer paper disc diffusion method. Several assays have been performed on the medicinal plant Oldenlandia corymbosa (OC). The results have been compared to those obtained from a traditional medical plant, Ocimum sanctum (OS) for the first time to our knowledge. Results showed that OS contains a higher quantity of polyphenols, flavonoids, and has higher antioxidant potential with respect to OC. Similar trends were observed for polysaccharides contents. In contrast, OC contains a higher quantity of tannins, alkaloids, and protein and higher in vitro antibacterial and anti-diabetic properties. HPLC-DAD-based profiling of eight important phenolic constituents viz. Gallic acid, catechin hydrate, chlorogenic acid, caffeic acid, syringic acid, p-coumaric acid, sinapic acid, coumarin, quercetin, and kaempferol, were performed. The current study concluded that Oldenlandia corymbosa has many bioactive phenolics in considerable amounts compared to the highly established medicinal herb OS leaves extracts. The current study demonstrates the pharmacological significance of Oldenlandia corymbosa that may generate enthusiasm among researchers and those working in the pharmaceutical industry.