A Comprehensive Evaluation On Psidium Guajava For The Highest Potential Antioxidant And Antimicrobial Capacity On Antiacne Product

Abstract

The aim of this study is to investigate the effect of dried method as well as leaf maturity which influences factors of total phenolic and flavonoid contents yielded, antioxidant and antimicrobial activity of guava leaf extracts. A colorimetric assay, 2,2-diphenyl 1-picrylhydrazyl (DPPH) free radical scavenging assay, minimum inhibitory concentration (MIC) and disc diffusion methods were used to evaluate the potent of extracts in terms of total phenolic contents (TPC) and flavonoid contents (TFC), antioxidant activities, and antimicrobial activities, respectively. The study of extraction conditions showed that dry leaves were dominant rather than fresh leaves, additionally, in terms of leaf ages, dry young samples yielded the highest activity among others, regarding TPC, TFC, antioxidant capacities. This indicated that the effects of pretreatments including method extraction and leaf maturity greatly influenced the activities of leaves. Particularly, for total phenolic and flavonoid contents, the young leaf extracts yielded the higher values rather than that of old leaf extracts, which were 1517.22 ± 41.94 (mg GAE/g LE) and 1066.67 ± 115.47 (mg QE/g LE), respectively. The young guava leaves of hot water extraction exhibited the potent antioxidant power while comparing to that of commercial vitamin C of 294.58 ± 1.46 and 112.10 ± 0.48 (µg/mL), respectively. However, the extracts of guava leaves in both leaf age categories showed no inhibition against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Furthermore, guava leaf extracts in the face serum product also demonstrated its high antioxidant potential of 79.69 ± 0.70 (%) against commercial Bio-essence antioxidant lotion, which was 24.32 ± 3.96 (%).