ABSTRACT

Comparative assessment of the phytochemical content and antioxidant potential of Azadirachta indica (neem) and Parquetina nigrescens (bullock) is the aim of this study. In order to achieve this, both plants were harvested from the botanical garden, University of Ibadan. The leaves were removed from the stem, washed with running water to remove contaminants, oven dried at 37˚C and milled into powder.

The qualitative analyses of both plants were investigated after which six selected phytochemicals present in both plants from the qualitative analysis (phytic acid, total phenolics, alkaloids, saponin, flavonoids and tannin) were analyzed quantitatively using standard methods. The study also investigated the antioxidant potential of both plants using Ascorbic acid, α, α-diphenyl-β-picrylhydrazyl (DPPH) and Ferric Ion Reducing Antioxidant Power (FRAP) as case studies. 

The result of the qualitative analysis showed that both plants contained variety of the phytochemicals. The quantitative analyses showed that these phytochemicals are present in different concentrations. The concentration of phytic acid and total phenolics were significantly higher in A. indica (1.1536% and 9.19 mg/g) when compared with P. nigrescens (0.972% and 7.71 mg/g) respectively at p< 0.05. It was also observed that A. indica had lower concentrations in alkaloids, saponin, flavonoids and tannin (0.0123%, 0.0050%, 0.02% and 11.5mg/g) when compared with P. nigrescens (0.0363%, 0.0093%, 0.03% and 16.5mg/g) respectively. Also tested for were antioxidants (ascorbic acid, DPPH and FRAP). The concentration of ascorbic acid was significantly higher in A. indica (26.42mg/g) when compared with P. nigrescens (17.61mg/g) at p< 0.05. α, α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging potential of A. indica and P. nigrescens was investigated respectively at different concentrations with A. indica having the higher radical scavenging potential. The scavenging potential of DPPH was found to increase with increasing concentration of the extracts.

These phytochemicals and antioxidants have been reported to have biochemical and physiological effects which includes, anticarcinogenic effects, lowering serum cholesterol levels, scavenging free radicals, etc. In this study, it was observed that both plants are rich in phytochemicals and possess antioxidant potential. Hence, they might act as prophylactic and remedy for different diseases, such as cancer, atherosclerosis, obesity, etc. Parquetina nigrescens might be more potent than Azadirachta indica in acting as a prophylactic and remedy for different diseases.