Crystal Guava (Psidium guajava L. “Crystal”): Evaluation of In Vitro Antioxidant Capacities and Phytochemical Content

Abstract

Free radicals can cause many diseases, such as cancer. Antioxidant is a compound that could scavenge free radicals. One of the natural antioxidants is guava. The goals of this research were to investigate the antioxidant activity of leaves and fruit of crystal guava by determining the value of the Antioxidant Activity Index (AAI) using DPPH, CUPRAC, and FRAP; evaluate the total phenolic content (TPC) and total flavonoid content (TFC); analyse the correlation between the TPC and TFC with AAI DPPH, CUPRAC, and FRAP, and analyse the correlation between the 3 methods. Extraction was performed by the reflux method using n-hexane, ethyl acetate, and ethanol. Determination of AAI DPPH, CUPRAC, FRAP, the TPC, and the TFC was performed by UV-visible spectrophotometry. The correlation of the TPC and TFC with AAI DPPH, CUPRAC, and FRAP and, also, the correlation of the 3 methods were investigated by Pearson’s method. The antioxidant activity of leaves and fruit extracts of crystal guava showed AAI DPPH in the range of 0.33–56.46, CUPRAC 0.20–7.31, and FRAP 1.65–59.89. The highest TPC was given by ethanol leaf extracts (49.55 ± 1.45 g GAE/100 g), while the highest TFC was for n-hexane leaf extracts (9.68 ± 0.210 g QE/100 g). The TPC of leaves extract had a significantly positive correlation with AAI DPPH, CUPRAC, and FRAP. AAI DPPH, AAI CUPRAC, and AAI FRAP of leaves and fruit extract of crystal guava showed a significantly positive correlation. In general, leaves extract had strong antioxidant activity by the three methods. For the highest antioxidant activity, ethanol was the best solvent for extraction leaves and ethyl acetate for extraction fruit of crystal guava. The TPC in leaves extract contributed to the antioxidant activity by DPPH, CUPRAC, and FRAP methods. The Antioxidant activity of leaves and fruit extracts of crystal guava was linear by the three methods.

Unused Parts of Jackfruit (Artocarpus heterophyllus): Prospective In Vitro Antioxidative Activity

“…Another study reported the antioxidant activity of A. heterophyllus in IC 50 value [31]. If the antioxidant activity was determined using IC 50 , then the Pearson's correlation must be significantly negative [32].…”

Synergistic Efficacy of Phytochemical, Antioxidant and Bactericidal Properties of the Aerial Essential Oil of Laggera crispata

“…The DPPH antioxidant and free radical scavenging of the essential oil was determined using DPPH method 40 . Briefly stock solution of the essential oil (1.0 mgml -1 ) was diluted in methanol to different concentrations of 1000, 100 and 10 μgml -1 .…”

“…A o is the absorbance of the blank solution and A is the absorbance of the essential oil. The IC 50 , the concentration giving 50% inhibition of DPPH, was read off a graph of I% (percentage inhibition) versus extract concentration 40 .…”

“…The AAI was calculated using the formula: AAI value of < 0.5 was rated as weak; 0.5-1.0 was considered as moderate; 1.0-2.0 was classified as strong, and value > 2.0 was considered as very strong 40 .…”

Identification of catechin in ethyl acetate phase and determination of redox profile of the Anacardium occidentale L. through electrochemical techniques

“…The absorbances at all concentrations tested at 60 min were converted into a percentage of inhibition (PI). The antioxidant activity was also expressed by the antioxidant activity index (AAI), calculated according to Hartati, Nadifan and Fidrianny (2020) [19], according to the equation: AAI = % DPPHREM (FINAL) (µg mL -1 ) / IC50 (µg mL -1 ).…”