Antioxidants have received much attention in modern society and progressive research have shown that these molecules can help prevent diet-related non-communicable diseases and neurodegenerative diseases by scavenging free radicals, mainly reactive oxygen species, produced during cell metabolism [1][2]. Fruits and vegetables abound in antioxidants and these bioactive molecules are also present in varying quantities in nuts, grains, spices and some meats [3]. Studies have shown that fruits and vegetables increase blood levels of antioxidants significantly and reduce concentrations of markers that are elevated during oxidative stress, such as malondialdehyde and 8-hydroxydeoxyguanosine [4]. Numerous investigations have also reported that daily intake of fruits and vegetables increased the oxygen radical absorption capacity (ORAC) of blood, representing higher antioxidant defence of the body [3]. Though malnutrition has been a challenge in Ghana and Africa as a whole, the potential of many indigenous fruits and vegetables to combat it has not yet been exploited [5]. There is little documentation on their high phytochemical composition and bioactivities hence data on their antioxidant activities is scant [6][7]. In our study, we aimed to investigate the antioxidative potency of 7 wild edible fruits, fruit parts and vegetables of Ghana, namely: Chrysophyllum albidum G. Don, Chrysophyllum perpulchrum Mildbr. ex Hutch. & Dalziel, Chrysophyllum subnudum Baker, Delpydora gracilis A. Chev., Landolphia dulcis var. barteri (Stapf) Pichon, Morinda morindoides (Baker) Milne-Redh.and Sterculia tragacantha Lindl. Samples were collected from the Eastern, Western and Western North regions of Ghana in December 2020. Methanolic extracts were obtained from the dried plant material and the antioxidative activity of each extract was evaluated in vitro using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging [8] and oxygen radical absorbance capacity (ORAC) [9] methods. The fruit pulp (mesocarp) of C. subnudum which exhibited the best scavenging activity against the DPPH radical with a remarkable IC50 ± SD value of 45.18 ± 8.61 µg/ml showed an activity of 75.53 ± 8.12 µg/ml in the ORAC assay. Contrastingly, the fruit pulp (mesocarp) of C. albidum demonstrated the best antioxidative activity of 18.54 ± 0.27 µg/ml among the samples in the ORAC assay but recorded a value of 95.63 ± 13.24 µg/ml in the DPPH assay. The seed pulp and epicarp of C. albidum also recorded significant activities of 37.34 ± 6.6 µg/ml and 58.13 ± 3.42 µg/ml respectively in the ORAC assay. Moderate to weak antioxidative effects were observed in the DPPH and ORAC assays for the remaining samples. This study suggests some degree of radical specificity in the scavenging abilities of potent antioxidative fruit parts and provides evidence that the fruit parts of C. albidum and the fruit pulp C. subnudum exhibit significant antioxidant properties when evaluated using both electron and hydrogen atom transfer methods hence they may serve as effective antioxidants which can be used in the food and pharmaceutical industry.
Acknowledgements: Czech University of Life Sciences Prague (project IGA IGA.20213109) supported this research.
CSIR-Plant Genetic Resources Research Institute, Box 7, Bunso, E/R, Ghana
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