Title : Color characteristic, active compounds and antioxidant activity of Java tea
Abstract:
Java tea or cat's whiskers (Orthosiphon aristatus (Blume) Miq.) is herbaceous shrubs with whitish flower resembling a cat’s whiskers. Its dried aerial part has been wildly used as traditional herb for the treatment of fever, epilepsy, gallstones, hepatitis, rheumatism, hypertension, syphilis and renal calculus. This plant also shows antioxidant, antibacterial, hepatoprotective, anti-inflammatory, cytotoxic, antihypertensive, and vasodilatation properties. However, apparent color of commercial Java tea is various. Therefore, this work was aimed to study color characteristic, active compounds and antioxidant activity of Java tea. The work was performed by analyzing fifty Java tea commercial products. Apparent color of Java tea samples was range from light yellowish brown to dark brown. CIELab (L*, a* and b*) and CIELCh (L*, C* and h) which numerical system proposed by Commission Internationale de l’Eclairage and the Munsell Color system in numerical scale were determined. DPPH radical scavenging activity and ferric reducing antioxidant power (FRAP) were assay for antioxidant activities. Active compounds, including caffeic, rosmarinic, sinensetin, eupatorin and betulinic were analyzed by using UHPLC. The results showed that L*, a*, b*, C* and h of Java tea were 44.42±3.48, 3.86±1.42, 21.30±2.36, 21.69±2.43 and 79.85±3.53, respectively. The most common Munsell color code of Java tea samples was 5Y 5/6. Among 5 active compounds, rosmarinic was major compound with 3.96±1.97%. While the others compound contents were less than 0.5%. DPPH radical scavenging activity and FRAP value were 2.79±1.10 and 2.85±1.72 g GAE/kg, respectively. Though, almost all CIE color parameters were significant correlated with active compounds and antioxidant activities, the correlation values were low to negligible. It could be concluded that color is not appropriate quality indicator for Java tea product.
