Phytochemicals and antioxidant properties of the leaves of wild guava varieties grown in Sri Lanka

Abstract

Guava (Psidium guajava Linn.) is well-known throughout the world for its food, nutritional, and medicinal properties. Several guava cultivars/varieties are available in Sri Lanka, which can be classified as common, wild, or introduced. Though common guava has been extensively studied for its phytochemistry and pharmacology, only a few studies on wild varieties has been available so far. Therefore, this study focused on the investigation of phytochemical constituents and antioxidants capacity of two main wild guava varieties grown in Sri Lanka namely, Psidium guajava (cv. Getta-pera) and Psidium guineense (cv. Embul-pera). An Ultrasound-assisted-extraction technique was used to extract plant constituents, and water was used as the solvent. The phytochemicals were qualitatively and quantitatively analyzed using standard methods whereas the antioxidant capacity was determined using the DPPH and FRAP assays. Phytochemical screening revealed that both varieties contain most of the important phytochemicals. Though both showed higher anti-oxidant activity, Embul-pera had the highest in both the FRAP and DPPH assays, with 612.69±0.50 mg Trolox Eq/g and IC50 value of 191.69±0.25 ppm respectively. The highest level of all quantified phytochemicals, particularly polyphenolic content (327.87±0.23 mg GAE/g extract) was found in Embulpera. As a conclusion, two wild guava varieties considered in the study contain a diverse phytochemical profile and higher antioxidant properties similarity to the common guava. It can be recommended that Getta-pera" and "Embul-pera" are excellent alternatives to be used in functional foods and nutraceuticals preparation and hence to promote the cultivation as economic plants.

Sesquiterpenes and monoterpenes from different varieties of guava leaf essential oils and their antioxidant potential

“…The FRAP assay of EO was carried out using standard methods reported in the literature [ 14 , 15 , 16 ]. About 3.0 mL of freshly made FRAP reagent [300 mM acetate buffer (pH-3.6): 10 mM TPTZ (in 40 mM HCl): 20 mM FeCl 3 in a 10:1:1 ratio] was mixed with 100 μL of sample solution.…”

Investigations of chemical compositions and antioxidative potential of essential oils isolated from the leaves of two Garcinia species

“…Trolox ((±)-6-hydroxy-2, 5, 7, 8-tetramethylchromane-2-carboxylic acid) was used as a standard, and the results were expressed in μL Trolox Eq/L. [ 11 12 ]…”

Chemical profile and antioxidants property of Eryngium foetidum L. leaves – use of HPLC methods to optimize extracting solvents to be used in functional food development

“…Quantification of some phytochemicals 0.10 g of methanolic extract was dissolved in 0.25 ml of DMSO and diluted with 100.0 ml of methanol to make a 1000 ppm concentration. The prepared solution was then utilized for phytochemicals spectrophotometric measurements such as total phenolics (TPC), total tannins (TTC), total flavonoids (TFC), terpenoids (TC), saponins (SC), and alkaloids contents (AC) as described in the literature (Kokilananthan et al, 2020;2021;2022a;2022c;Shanthirasekaram et al, 2021).…”

“…DPPH radical scavenging assay and ferric reducing antioxidant power (FRAP) assay were applied to determine the antioxidative potential of methanolic extract and the EO of E. foetidum leaves (Kokilananthan et al, 2020;2021;2022a;2022c;Shanthirasekaram et al, 2021). The IC 50 value for free radical scavenging activity of methanolic extract was determined using a percentage of radical scavenging effect vs. concentration plot where ascorbic acid and Trolox were used as standards of antioxidants.…”