Phytosterol and α-Lipoic Acid Conjugates: Synthesis, Free Radical Scavenging Capacity and RP-LC-MS-APCI Analysis

Abstract

Plant sterols (PS) are bioactive compounds effective in reducing plasma cholesterol. Fatty acid esters of PS have improved solubility and blending properties when utilized in various food products. Naturally occurring α-lipoic acid (LA) and its reduced form dihydrolipoic acid (DHLA) are known for their antioxidant activity. In addition, they have shown an array of health benefi cial properties against obesity, diabetes, cancer, cardiovascular and infl ammatory diseases etc. Different LA conjugates have been reported to have increased bioactivity compared to the parent compounds. The objective of this study was to synthesize PS esters of LA (PSLA) and DHLA (PSDHLA) in order to increase their cholesterol lowering effect and reducing the risk of atherosclerosis with additional health benefi ts e.g. against oxidative stress.Synthesis of PSLA and PSDHLA was performed with a pure PS mixture of β-sitosterol, stigmasterol, campesterol and brassicasterol. The free radical scavenging capacity of the conjugates was assessed by the DPPH method. Remaining percentage of DPPH free radicals was measured at the steady state for different concentrations of PSLA and PSDHLA. High free radical scavenging capacity was observed for PSDHLA compared with PSLA. Effi cient concentration EC 50 as a molar ratio for PSDHLA was 0.43. The derivatives were analyzed by RP-HPLC-MS-APCI. The order of the elution times of the compounds observed in HPLC-MS analysis was PS< PSDHLA< PSLA. Baseline separation was not achieved between campesterol and stigmasterol and their derivatives. These compounds could be identifi ed by their characteristic fragment ions from the mass spectral data.

Antimicrobial activity of the fiber produced by “pochote” <i>Ceiba aesculifolia</i> subsp. <i>parvifolia</i>

“…Flavonoids have a variable number of hydroxyl phenolic groups and excellent ferric and other transition metal chelation properties, which confer a significant antioxidant capacity (Martínez et al, 2002) and play an important role in plant defense and signaling for reproduction, pathogenesis and symbiosis (Rijke et al, 2006), The sterols identified through chromatographic techniques, such as campesterol and stigmasterol, have demonstrated antioxidant properties in vitro and in vivo (Madawala et al, 2012). These sterols are also associated with pathogen defense, which could be related to the activity against bacteria and fungi observed in this study (Ramakrisha and Ravishankar, 2011).…”

Plant Sterols: Chemical and Enzymatic Structural Modifications and Effects on Their Cholesterol-Lowering Activity

“…In addition to phenolic acids, lipoic acid and dihydrogen lipoic acid also showed a good antioxidant capacity. To provide better physiological functions, plant sterol esters of lipoic acid and dihydrogen lipoic acid were also synthesized. , Madawala et al synthesized phytosterol lipoate and phytosterol dihydrolipoate using a chemical method in the presence of DMAP and 1-ethyl-3-(3-(dimethylamino)­propyl)­carbodiimide hydrochloride . By contrast, phytosterol dihydrolipoate displayed a better scavenging capacity of 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical.…”

“…125,126 Madawala et al synthesized phytosterol lipoate and phytosterol dihydrolipoate using a chemical method in the presence of DMAP and 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide hydrochloride. 125 By contrast, phytosterol dihydrolipoate displayed a better scavenging capacity of 1,1-diphenyl-2picrylhydrazyl (DPPH) free radical. Wang et al developed an enzymatic route to synthesize phytosterol lipoate with a conversion of 71% using C. rugosa lipase as a catalyst under optimal conditions for 96 h. 126 The antioxidant ability of phytosterol has been greatly improved by conjugating with lipoic acid.…”

Development and characterization of phytosterol nanoemulsions and self-microemulsifying drug delivery systems

“…Phytosterols(PS) are triterpenes, an important component of plant cells, and are commonly found in seeds, vegetable oils and grains. Common in nature are β-sitosterol, campesterol, stigmasterol and ergosterol [1].It has the physiological functions of lowering blood lipid [2,3] , lowering cholesterol [4][5][6] , preventing cardiovascular disease [7],anti-cancer [8], anti-oxidation, scavenging free radicals [9,10], enhancing immunity [11], anti-inflammatory [12,13] and so on. Especially in reducing blood lipids, PS and cholesterol have similar molecular structure, which can competitively inhibit the absorption of cholesterol in the human intestinal tract, thereby reducing blood lipids [14].…”