Senyawa Antioksidan dari Ekstrak n-Heksana Daun Asam Jawa (Tamarindus indica L.) dari Banyuresmi, Garut - Indonesia - Irda Fidrianny; Ellis Siti Zahidah; Rika Hartati (School of Pharmacy Institut Teknologi Bandung, 2014)
Pada proses metabolisme tubuh radikal bebas terbentuk secara alami, dalam jumlah tertentu diperlukan tubuh karena merupakan bagian dari sistem pertahanan tubuh. Jika tubuh terpapar radikal bebas berlebihan dan terus menerus dapat menyebabkan kerusakan sel bahkan kematian sel. Antioksidan merupakan senyawa yang dapat menghambat reaksi oksidasi dengan mengikat radikal bebas dan molekul yang sangat reaktif. Berdasarkan beberapa penelitian, daun asam Jawa (Tamarindus indica L.) diketahui memilki efek antioksidan. Selain itu, daun asam Jawa telah banyak dimanfaatkan oleh masyarakat untuk mengobati berbagai macam penyakit. Penelitian ini bertujuan untuk menguji aktivitas antioksidan berbagai ekstrak daun asam Jawa dengan DPPH, menetapkan IC50 peredaman DPPH, menetapkan kadar fenol total, flavonoid total, karotenoid total dari masing-masing ekstrak, menganalisis korelasi fenol total, flavonoid total, dan karotenoid total terhadap aktivitas peredaman DPPH dan mengisolasi senyawa aktif antioksidan dari ekstrak daun asam Jawa. Simplisia daun asam Jawa diekstraksi dengan refluks menggunakan tiga pelarut dengan kepolaran meningkat yaitu n-heksana, etil asetat, dan etanol. Dilakukan pemantauan pada setiap ekstrak secara kromatografi lapis tipis (KLT). Uji aktivitas peredaman radikal bebas DPPH (2,2-difenil-1-pikrilhidrazil), IC50 peredaman DPPH, penentuan flavonoid total, fenol total, karotenoid total dilakukan dengan spektrofotometri ultraviolet-sinar tampak dan analisis korelasinya dengan aktivitas peredaman DPPH menggunakan metode Pearson. Ekstrak n-heksana difraksinasi secara kromatografi cair vakum (KCV). Fraksi ke-4-5 selanjutnya dilakukan subfraksinasi secara kromatografi kolom. Subfraksi 31 dimurnikan dengan KLT preparatif dan dilakukan uji kemurnian secara KLT. Simplisia daun asam Jawa (Tamarindus indica L.) mengandung flavonoid, fenol, terpenoid, steroid/triterpenoid. Ekstrak etanol daun asam Jawa (BJ ekstrak 1 % 0,81 g/mL) menunjukkan aktivitas peredaman DPPH tertinggi (66,74%) dengan IC50 peredaman DPPH 2,05 µg/mL, fenol total 6,17 g GAE/100 g, flavonoid total 3,22 g QE/100 g, karotenoid total 0,35% g BE/100 g. Satu senyawa antioksidan E diperoleh dari ekstrak n-heksana. Aktivitas peredaman DPPH ekstrak etanol daun asam Jawa berbeda bermakna terhadap ekstrak etil asetat dan ekstrak n-heksana (p<0.05). Golongan fenol merupakan kontributor utama pada aktivitas antioksidan ekstrak daun asam Jawa dengan metode DPPH. Senyawa antioksidan E merupakan senyawa aglikon flavonol yang mempunyai -OH bebas pada C-3 dan diduga mempunyai -OH bebas pada cincin A dan atau B.Kata kunci: antioksidan, DPPH, asam Jawa, daun, ekstrak n-heksana, isolat EAbstractIn metabolism process free radicals are formed naturally. The body needs a certain amount as a part of the body's defense system. If body is exposed by free radicals excessively and continuously can cause cell damage and even cell death. Antioxidant are compounds that can inhibit the oxidation reaction by binding to free radicals and highly reactive molecules. Based on several studies, tamarind (Tamarindus indica L.) leaves were known to have the effect of antioxidants. In addition, tamarind leaves have been used by people for treating various diseases. This research aimed to test the antioxidant activity of various extracts of tamarind leaves by DPPH method, determine IC50 DPPH scavenging activity, total phenolic, total flavonoids, total carotenoid of each extract, analyze their correlation with DPPH scavenging activity and isolation antioxidant compound of tamarind leaves extract. Crude drug of tamarind leaves was extracted by reflux aparatus using three solvents with increasing polarity, n-hexane, ethyl acetate and ethanol. Each extract were monitored by TLC, IC50 DPPH scavenging activity, total phenolic, total flavonoids, total carotenoid of each extracts by ultraviolet-visible spectrophotometry and their correlation with DPPH scavenging activity by Pearson method. N-hexane extract was fractionated by vacuum liquid chromatography. Then fractions 4-5 were subfractionated by column chromatography. Subfraction 31 was purified using preparative thin layer chromatography (TLC) and purity test was performed by TLC. Crude drug of tamarind (Tamarindus indica L.) leaves contained flavonoids, phenolic compound, terpenoids, steroids / triterpenoids. Ethanol extract of tamarind leaves (MW 1 % extract was 0.81 g / mL) showed the highest DPPH scavenging activity (66.74 % ) with IC50 of DPPH scavenging activity 2.05 µg/mL. Total phenolic, flavonoid, carotenoid content were 6.17 g GAE/100 g, 3.22 g QE/100 g and 0.35 g BE/100 g, respectively. An antioxidant compound E was obtained from n-hexane extract. The antioxidant activity of ethanol extract significantly different with n-hexane extract and ethyl acetate extract (p<0.05). Phenolic compounds were the major contributor in tamarind leaves extract using DPPH assay. Antioxidant compound E was flavonol aglycone that had free -OH group in C-3 and expected had free -OH in ring A and or ring B.Keywords: antioxidant, DPPH, tamarind, leaves, n-hexane extract, isolate E