No abstract

Cardiovascular protective functions of bamboo shoot angiotensin converting enzyme (ACE) inhibitory peptide (BSP) from bamboo shoot were evaluated, including antihypertensive effect on spontaneously hypertensive rats (SHRs) and antihyperlipidemic effect on high-fat-diet-induced rats. Thirty-day antihypertensive effects of BSP on SHRs were assayed. Asp-Tyr [10 mg/day kg body weight (BW)] and BSP (50 mg/day kg BW) significantly reduced ACE activity in lung at the same level (p < 0.05), while BSP (50 mg/day kg BW) reduced systolic blood pressure (SBP) more effectively for its phenolic compounds, such as ferulic acid and p-coumaric acid, which when combined with ACE inhibitor exert a synergistic effect. BSP could significantly reduce SBP, improve oxidant stress status (GSH-Px, SOD, TAC and MDA), and increase NO level in serum and NOS activity in kidney. BSP decreased total cholesterol (TC), triglyceride (TG), and low-density lipoprotein cholesterol (LDL-c) content and MDA level of hyperlipidemic rats, which might contribute to the ACE inhibitory capacity of Asp-Tyr and the fatty acid synthase inhibitory activity of phenolic compounds.

In this paper, aqueous extract fractions from byproducts of the processing of canned bamboo shoots, including boiled water, filled liquid, and squeezed juice, were obtained by 5 kDa molecular cutoff membranes and marcoporous resin DA201-C treatment. The enriched bamboo shoot angiotensin converting enzyme (ACE) inhibitory peptide preparation fraction (called BSP for short) was extracted with ethyl acetate and n-butanol. The ethyl acetate fraction and n-butanol fraction exhibited higher antioxidant capacities than the leaving water fraction (BSML), which was attributed to the higher phenolic acid and flavonoid content of both fractions, while BSML exhibited the strongest ACE inhibitory activity. Sephadex G-15 gel filtration and semipreparative high-performance liquid chromatography were used for further purification of bamboo shoot ACE inhibitory peptide from BSML. Asp-Tyr was identified as the key active component by ultra-high-performance liquid chromatography and electrospray ionization tandem mass spectrometry. A short-term antihypertensive assay stated that both Asp-Tyr [10 mg day(-1) (kg of body weight)(-1)] and BSP [50 mg day(-1) (kg of body weight)(-1)] could significantly reduce the systolic blood pressure of spontaneously hypertensive rats (3-6 h). This study provides further examples of utilization of byproducts from the processing of canned bamboo shoots for the prevention of hypertension and attenuation of oxidative stress.

AOB-w is a water-soluble antioxidant extracted from bamboo leaves, containing four flavone C-glucosides (orientin, isoorientin, vitexin, and isovitexin) as functional components. Flavone C-glucoside esters were firstly synthesized by three lipases (CALB, RM IM, and TL IM) in an organic solvent system or a solvent-free system. Results indicated that C12 fatty acid ester exhibited the optimal antioxidant capacity; CALB was the most efficient lipase in both systems; and higher conversion yields were achieved in a solvent-free system. Highest conversion was obtained with 1% water content for CALB and 2% water content for RM IM and TL IM. All lipases displayed absolute 6 00 -regioselectivities with monoester. It is required to consider both hydrophobicity and antioxidant capacity in order to prepare high-efficiency oil-soluble antioxidants. Regression equations were built up to illuminate the relationship between conversion yield of flavone C-glucoside and antioxidant capacity of its corresponding ester. The highest antioxidant capacity could be achieved when conversion yield was nearly 60% for flavone C-glucosides. Based on reaction parameters of flavone C-glucosides, high-efficiency eAOB-o was prepared, which could be expected as an excellent oil-soluble antioxidant in lipids.Practical applications: Water-soluble antioxidant of bamboo leaves (AOB-w) is a natural food antioxidant extracted from bamboo leaves, with four flavone C-glucosides (orientin, isoorientin, vitexin, and isovitexin) as functional components. This study aimed to provide a practical procedure to prepare high-efficiency lipid antioxidant by enzymatic acylation. Based on the optimal parameters from the synthesis of flavone C-glucoside esters, a high-efficiency oil-soluble antioxidant of bamboo leaves (eAOB-o) was prepared. eAOB-o exhibited higher antioxidant capacity than cAOB-o, which has been approved as a food antioxidant in China. Abbreviations: AOB-w, water-soluble antioxidant of bamboo leaves; BLFs, bamboo leaves flavonoids; CALB, Candida antarctica lipase B; cAOB-o, oil-soluble antioxidant of bamboo leaves synthesized by chemical acylation; eAOB-o, oil-soluble antioxidant of bamboo leaves synthesized by enzyme; ESI À , electrospray negative ionization; LDL, lowdensity lipoprotein; MS, mass spectrum; RM IM, Rhizomucor miehei lipase; TLC, thin-layer chromatography; TL IM, Thermomyces lanuginosus lipase 1636Eur.

No abstract