Abstract:
Guava (Psidium guajava L.) is a tropical fruit, rich in nutrients such as vitamin C, phenolic compounds, pectin and insoluble fiber. We focus on Pansithong, Thai original and Kimju grown locally commercial in Thailand by extracting them with water, 40%ethanol and Simulated Gastrointestinal Digestion (SGD) to analyze total polyphenolic compounds, DPPH scavenging activity, superoxide anion scavenging activity, hydroxyl radical scavenging activity anti-melanogenesis against tyrosinase, total phenolic acid and total vitamin C was found types guava and extracted conditions were the factor that have significant difference (P<0.05). The results showed that Pansithong contained the highest of polyphenol compounds and DPPH scavenging activity (IC₅₀ = 2.76 mg/mL). Moreover, the superoxide scavenging abilities generated in a PMS/NADPH system Thai original (IC₅₀ = 41.47 mg/mL) showed the highest of superoxide anion scavenging activity using 40% ethanol. The hydroxyl radicals were generated by the Fenton system was found Pansithong that used the water for extraction was the highest ability, whereas Thai original that used 40% ethanol for extraction was the highest. Kimju guava was extracted by using SGD demonstrated the highest hydroxyl properties. The anti-melanogenesis against tyrosinase found that Kimju showed the highest extracted (IC₅₀ = 290.71 mg/mL) by water. To analyze contained phenolic acid and Vitamin C determine by HPLC. The highest amounts of ferulic acid that was found in Kimju (14.00 mg/100g) by using 40% ethanol. While, the highest amounts of ascorbic acid were found in Kimju (159.97 mg/100g) using water extracts. Therefore, the effect of guava extracts may have a strong potential for use protective effect in human health.
