Chami Arumughan

Chemical composition and in vitro antioxidant studies on Syzygium cumini fruit.

Syzygium cumini, widely known as Jamun, is a tropical tree that yields purple ovoid fleshy fruit. Its seed has traditionally been used in India for the treatment of diabetes. Based on the available ethno-pharmacological knowledge, further studies were extended to understand the chemical composition and antioxidant activities of three anatomically distinct parts of fruit: the pulp, kernel and seed coat. Fruit parts, their corresponding ethanol extracts and residues were evaluated for chemical composition. The alcoholic extract was evaluated for its antioxidant potential against DPPH(•), OH(•), O(2) (•-) and lipid peroxidation. The whole fruit consisted of 666.0 ± 111.0 g kg(-1) pulp, 290.0 ± 40.0 g kg(-1) kernel and 50.0 ± 15.0 g kg(-1) seed coat. Fresh pulp was rich in carbohydrates, protein and minerals. Total fatty matter was not significant in all three parts of fruit. Detailed mineral analysis showed calcium was abundant in all fruit parts and extracts. Total phenolics, anthocyanins and flavonoid contents of pulp were 3.9 ± 0.5, 1.34 ± 0.2 and 0.07 ± 0.04 g kg(-1), respectively. Kernel and seed coat contained 9.0 ± 0.7 and 8.1 ± 0.8 g kg(-1) total phenolics respectively. Jamun pulp ethanol extract (PEE), kernel ethanol extract (KEE) and seed coat ethanol extract (SCEE) showed a high degree of phenolic enrichment. DPPH radical scavenging activity of the samples and standards in descending order was: gallic acid > quercetin > Trolox > KEE > BHT > SCEE > PEE. Superoxide radical scavenging activity (IC(50)) of KEE was six times higher (85.0 ± 5.0 µg mL(-1)) compared to Trolox (540.0 ± 5.0 µg mL(-1)) and three times compared to catechin (296.0 ± 11.0 µg mL(-1)). Hydroxyl radical scavenging activity (IC(50)) of KEE was 151.0 ± 5.0 µg mL(-1) which was comparable with catechin (188.0 ± 6.0 µg mL(-1)). Inhibition of lipid peroxidation of the extracts was also studied and their activity against peroxide radicals were lower than that of standard compounds (BHT, 79.0 ± 4.0 µg mL(-1); quercetin, 166.0 ± 13.0 µg mL(-1); Trolox, 175.0 ± 4.0 µg mL(-1); PEE, 342.0 ± 17.0 µg mL(-1); KEE, 202.0 ± 13.0 µg mL(-1) and SCEE, 268.0 ± 13.0 µg mL(-1). Copyright

Effect of polymerization on antioxidant and xanthine oxidase inhibitory potential of sea buckthorn (H. rhamnoides) proanthocyanidins.

Inhibitory potential of sea buckthorn (Hippophae rhamnoides L) seed proanthocyanidins against oxidative stress and xanthine oxidase activity was evaluated. Composition of antioxidant proanthocyanidins was profiled by analyzing the cleavage products obtained by the acid catalyzed hydrolysis in the presence of phloroglucinol. Catechin, epicatechin, gallocatechin, and epigallocatechin were found as the extension and terminal subunits of proanthocyanidins with an average degree of polymerization (ADP) of 14.7. Seed proanthocyanidins showed considerably high antioxidant and xanthine oxidase inhibitory potentials. Antioxidant and xanthine oxidase inhibitory capacity evaluation of proanthocyanidin fractions with varying ADP showed that proanthocyanidins with lower molecular size were more effective as superoxide anion (ADP ≤ 4.2) and hydroxyl radical (ADP ≤ 5.9) scavengers and xanthine oxidase (ADP ≤ 3.1) inhibitors. ADP of the studied proanthocyanidin fractions did not show significant influence on their DPPH and ABTS radical scavenging and ferric reduction capacities.

HPLC-DAD-MS/MS profiling of antioxidant flavonoid glycosides in sea buckthorn (Hippophae rhamnoides L.) seeds

This study was aimed at the chemical profiling of flavonoid glycosides in antioxidant (AO) fractions of sea buckthorn (Hippophae rhamnoides) seed. Seed fractions were evaluated for their DPPH, ABTS, superoxide and hydroxyl radical scavenging, ferric reduction, ferrous chelation and xanthine oxidase inhibitory capacities. HPLC-DAD-ESI-MS/MS analytical conditions for the profiling of seed flavonoids were optimized and the AO-rich fraction was analysed. Quercetin-3-O-rutinoside (5.9%), isorhamnetin-3-O-rutinoside (4.9%) and isorhamnetin-3-O-sophroside-7-O-rhamnoside (3.7%) were found as the major flavonoid glycosides in the fraction. Significant amounts of isorhamnetin-3-O-glucoside (2.8%), 3-O-sophroside-7-O-rhamnosides of quercetin (2.4%) and kaempherol (1.3%), and 3-O-glucoside-7-O-rhamnosides of quercetin (1.1%) and isorhamnetin (1.1%) along with their free forms: isorhamnetin (2.7%), quercetin (1.1%) and kaempherol (0.6%) were also found in the fraction. The identification of flavonoids as the major less polar AO phenolics in the seeds was rationalized by demonstrating the high AO activity of isorhamnetin, quercetin, kaempherol and quercetin-3-O-rutinoside.

Sea Buckthorn (Hippophae rhamnoides) Proanthocyanidins Inhibit In Vitro Enzymatic Hydrolysis of Protein

Interactions of phenolics with other food constituents and digestive enzymes are likely to have interference with the digestion and bioavailability of food and phenolics. In this study the effect of sea buckthorn proanthocyanidins on in vitro digestion of protein was evaluated. Optimization of the extraction conditions showed that maximum recovery of sea buckthorn proanthocyanidins was obtained with acidified acetone; water mixture (60% to 70%, v/v). Crude proanthocyanidin extracts thus prepared were purified using sephadex gel column chromatography and their average degree of polymerization and the effects on enzymatic hydrolysis of bovine serum albumin as influenced by their protein precipitation capacities were studied. Average degree of polymerization of proanthocyanidins in berry pulp, kernel, seed coat, and leaves was 7.4, 5.6, 8.2, and 10.6, respectively. The EC50 values for the protein precipitation by the PA of berry pulp, kernel seed coat, and leaves were 44.2, 44.1, 65.8, and 39.8 μg, respectively. Relative enzymatic hydrolysis of the protein-proanthocyanidin complexes was 44.1% to 60.3% for pepsin and 57.5% to 67.7% for trypsin. Interactions of sea buckthorn proanthocyanidins with food proteins and digestive enzymes might alter the protein digestibility and phenolic bioavailabilty.