Chan Eric W C, Soh Eu Ying, Tie Pei Pei, Law Yon Peng
Faculty of Applied Sciences, UCSI University, Cheras, Kuala Lumpur, Malaysia.
Pharmacognosy Res. 2011 Oct;3(4):266-72. doi: 10.4103/0974-8490.89748.
The role of non-polymeric phenolic (NP) and polymeric tannin (PT) constituents in the antioxidant and antibacterial properties of six brands of green, black, and herbal teas of Camellia sinensis were investigated.
Total phenolic content (TPC) and ascorbic acid equivalent antioxidant capacity (AEAC) were assessed using the Folin-Ciocalteu and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays, respectively. Minimum inhibitory dose (MID) against Gram-positive Micrococcus luteus, Staphylococcus aureus, and Bacillus cereus, and Gram-negative. Escherichia coli, Salmonella typhi, and Pseudomonas aeruginosa was assessed using the disc-diffusion method. Teas were extracted with hot water successively three times for one hour each time. The extracts were fractionated using Sephadex LH-20 column chromatography to obtain the NP and PT constituents.
Extraction yields ranged from 12 to 23%. Yields of NP fractions (70-81%) were much higher than those of PT fractions (1-11%), suggesting that the former are the major tea components. Ranking of antioxidant properties of extracts was green tea>black tea>herbal tea. For all six teas, antioxidant properties of PT fractions were significantly higher than extracts and NP fractions. Extracts and fractions of all six teas showed no activity against the three Gram-negative bacteria. Green teas inhibited all three Gram-positive bacteria with S. aureus being the least susceptible. Black and herbal teas inhibited the growth of M. luteus and B. cereus, but not S. aureus. The most potent were the PT fractions of Boh Cameron Highlands and Ho Yan Hor with MID of 0.01 and 0.03 mg/disc against M. luteus.
Results suggested that NP constituents are major contributors to the antioxidant and antibacterial properties of teas of C. sinensis. Although PT constituents have stronger antioxidant and antibacterial properties, they constitute only a minor component of the teas.
研究了非聚合酚(NP)和聚合单宁(PT)成分在六种品牌的绿茶、红茶和山茶属植物草本茶的抗氧化和抗菌特性中的作用。
分别使用福林-西奥尔特试剂法和2,2-二苯基-1-苦基肼(DPPH)法评估总酚含量(TPC)和抗坏血酸当量抗氧化能力(AEAC)。采用纸片扩散法评估对革兰氏阳性的藤黄微球菌、金黄色葡萄球菌和蜡样芽孢杆菌以及革兰氏阴性的大肠杆菌、伤寒沙门氏菌和铜绿假单胞菌的最小抑菌剂量(MID)。茶叶用热水连续提取三次,每次提取一小时。提取物通过葡聚糖凝胶LH-20柱色谱进行分离,以获得NP和PT成分。
提取率在12%至23%之间。NP组分的产率(70 - 81%)远高于PT组分的产率(1 - 11%),这表明前者是茶叶的主要成分。提取物抗氧化性能的排名为绿茶>红茶>草本茶。对于所有六种茶,PT组分的抗氧化性能显著高于提取物和NP组分。所有六种茶的提取物和组分对三种革兰氏阴性菌均无活性。绿茶对所有三种革兰氏阳性菌均有抑制作用,其中金黄色葡萄球菌最不易被抑制。红茶和草本茶抑制藤黄微球菌和蜡样芽孢杆菌的生长,但不抑制金黄色葡萄球菌。最有效的是金马仑高原宝茶和和兴白花油的PT组分,对藤黄微球菌的MID分别为0.01和0.03 mg/片。
结果表明,NP成分是中华茶抗氧化和抗菌特性的主要贡献者。虽然PT成分具有更强的抗氧化和抗菌特性,但它们仅占茶叶的一小部分。