Preliminary Phytochemical Screening and Comparative Antioxidant Potential of Garcinia indica (Thouars) Choisy, Garcinia gummi-gutta (L.) N. Robson and Garcinia talbotii Raizada ex. Santapau

Abstract

The Garcinia genus is well known for its fruit-bearing tree species found in the Indian subcontinent and tropics all over the world. Three species of Garcinia were selected for this study, viz., G. indica (listed as vulnerable in the IUCN Red list), G. gummi-gutta and G. talbotii (both listed as species of least concern in the IUCN Red list), all of which are endemic to the Western Ghats region. This study was undertaken to assess the phytochemical profile of the selected species as well as to determine their antioxidant potential. Extracts of leaves, bark and fruit rind prepared in 70% ethanol were used for the analysis. The major categories of bioactive compounds were found to be alkaloids, diterpenes, phenolics, flavonoids and coumarins, present in leaves, bark as well as fruit rind. Total Phenolic Content and Total Flavonoid Content were highest in G. gummi gutta bark, followed by G. indica bark and finally G. talbotii leaves. DPPH (2,2-diphenyl-1- picrylhydrazyl) and ABTS (2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)) assays were used to evaluate the antioxidant potential of the extracts and Ascorbic acid was used as the reference standard. Lowest IC50 values were exhibited by G. gummi-gutta bark extract (14.11 ± 0.21 μg/mL in DPPH assay; 5.37 ± 0.03 μg/mL in ABTS assay). IC50 values of G. indica bark extract were found to be 32.43 ± 0.63 μg/mL in DPPH assay and 12.08 ± 0.12 μg/mL in ABTS assay. Surprisingly, G. talbotii fruit rind showed an IC50 value of 34.18 ± 0.27 μg/ mL in DPPH assay, while G. talbotii leaves showed an IC50 value of 6.74 ± 0.09 μg/mL in ABTS assay, which is comparable to the efficacy of the standard. These findings hint at the strong antioxidant potential displayed by all three species, especially G. talbotii, which has not been extensively studied until now. This research work also signifies the importance of underutilized plant parts (bark and leaves) of well-known fruit trees belonging to Garcinia genus.