Antioxidant flavonoids from leaves of Polygonum hydropiper L

• Published in: Phytochemistry (Oxford) 2003, Vol.62 (2), p.219-228
• Main Authors: Peng, Zhao Feng, Strack, Dieter, Baumert, Alfred, Subramaniam, Ramanathan, Goh, Ngoh Khang, Chia, Tet Fatt, Ngin Tan, Swee, Chia, Lian Sai
• Format: Article
• Language: English
• Subjects: Antioxidant; Antioxidants - chemistry; Antioxidants - isolation & purification; Biological and medical sciences; Chemical constitution; Drug Synergism; Flavonoid; Flavonoids - chemistry; Flavonoids - isolation & purification; Fundamental and applied biological sciences. Psychology; Galloyl quercitrin; General pharmacology; Medical sciences; Molecular Structure; Pharmacognosy. Homeopathy. Health food; Pharmacology. Drug treatments; Plant Leaves - chemistry; Plant physiology and development; Polygonum - chemistry; Polygonum hydropiper L; Time Factors; Trolox equivalent antioxidant capacity (TEAC)
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/S0031-9422(02)00504-6

Ten flavonoid compounds were isolated from the dried leaves of Polygonum hydropiper L. (Laksa leaves), and identified as 3- O-α- l-rhamnopyranosyloxy-3′,4′,5,7-tetrahydroxyflavone; 3- O-β- d-glucopyranosyloxy-4′,5,7-trihydroxyflavone; 6-hydroxyapigenin; 6″- O-(3,4,5-trihydroxybenzoyl) 3- O-β- d-glucopyranosyloxy-3′, 4′, 5, 7-tetrahydroxyflavone; scutillarein; 6-hydroxyluteolin; 3′,4′,5,6,7-pentahydroxyflavone; 6-hydroxyluteolin-7- O-β- d-glucopyranoside; quercetin 3- O-β- d-glucuronide; 2″- O-(3,4,5-trihydroxybenzoyl) quercitrin; quercetin. Evaluation of the antioxidative activity, conducted in vitro, by using electron spin resonance (ESR) and ultraviolet visible (UV–vis) spectrophotometric assays, showed that these isolated flavonoids possess strong antioxidative capabilities. Measurement of the Trolox equivalent antioxidant capacity (TEAC) values, against ABTS (2,2′-azinobis(3-ethyl-benzo-thiazoline-6-sulphonic acid) radicals and phenyl- tert-butyl nitrone (PBN) azo initiator (AI) also showed strong anti-oxidative activity. The most powerful of the antioxidants was 2″- O-(3,4,5-trihydroxybenzoyl) quercitrin (galloyl quercitrin). A combination of two flavonoid compounds was tested for synergistic anti-oxidative capacity, but no significant improvement was observed. Ten flavonoid compounds were isolated and identified from the dried leaves of Polygonum hydropiper L. Among these, 2″- O-(3,4,5-trihydroxybenzoyl) quercitrin (galloyl quercitrin) showed high-yield occurrence and the strongest antioxidant activity. A combination of two flavonoid compounds was tested for synergistic antioxidative capacity, but no significant improvement was observed.