The extraction, characterization and antioxidant activity of polysaccharides from Choerospondias axillaris leaves were investigated in the present study. Two purified polysaccharide fractions, CALP-1 and CALP-2, were isolated from crude Choerospondias axillaris leaf polysaccharides (CALP) by DEAE-52 cellulose chromatography and Sephadex G-100 column chromatography. The characteristics of CAL-1 and CALP-2 were determined by using High-performance Gel Permeation Chromatography (HPGPC), High-Performance Anion-Exchange Chromatography, HPAEC (HPAEC-PAD) and Fourier transform infrared spectroscopy (FTIR). CALP-1 with molecular weight of 11.20 KDa was comprised of Rhamnose, Arabinose, Galactose, Glucose, Xylose, Mannose and galacturonic acid in a molar ratio of 5.16:2.31:5.50:27.18:1.00:0.76:1.07. CAL-2 with molecular weight of 8.03 KDa consisted of Rhamnose, Arabinose, Galactose, Glucose, and galacturonic acid at a ratio of 1.38:3.63:18.84:8.28:1.45. FTIR revealed that CALP-1 and CALP-2 were acidic polysaccharides. The antioxidant activity of crude CALP, CALP-1 and CALP-2 was evaluated in vitro. The fraction CALP-2 was demonstrated to be of polysaccharide nature containing a large percentage of Galactose but no Xylose and Mannose. The antioxidant activity assays showed that CALP-1 and CALP-2 exhibited antioxidant and scavenging activities on hydroxyl and DPPH radicals in vitro. Compared with pure polysaccharide, crude CALP exhibited stronger anti-oxidant activities. These results will provide a better understanding of Choerospondias axillaris leaf polysaccharide and promote the potential applications of Choerospondias axillaris leaf polysaccharide in the pharmacological field and as a natural antioxidant.

A self-designed reaction device was used as a promising equipment to investigate the oxidation characteristics and kinetics of rosin pentaerythritol ester (RPE) under UV irradiation. Photo-oxidation kinetics and the initial quantum yield (Φ) of RPE were calculated. The initial oxidation product of the photo-oxidation reaction—peroxide was analyzed by iodimetry. The peroxide concentration is related to the light intensity (I) and the temperature (T), and the increasing T and I would destabilize the RPE by accelerating peroxide forming. Photo-oxidation of RPE follows the pseudo first-order reaction kinetics. The relationship between activation energy and logarithm of light intensity (ln I) is linear, and it is expressed as Ea = −4.937ln I + 45.565. Φ was calculated by the photo-oxidation kinetics, and the average value of Φ was 7.19% in the light intensity range of 200–800 μW cm⁻². This research can provide fundamental information for application of RPE, and help obtain a better understanding of the stability of rosin esters.

Brown sugar (BS), Red granulated sugar (RGS) and White sugar(WS) are three key sweeteners and food additives in China. Notably, BS possesses significant nutritional value and has been widely used in Chinese medicine for its supportive therapeutic properties.This study evaluated the anti-fatigue, the amelioration of qi deficiency and blood stasis, as well as the antioxidant activities of these sugars using a zebrafish model. BS and RGS demonstrated significantly greater efficacy than WS in terms of both anti-fatigue effects and amelioration of qi Deficiency and blood stasis in the zebrafish model. Antioxidant assays revealed that BS, RGS, and WS (500 μg/mL) significantly enhanced superoxide dismutase (SOD) activity in zebrafish embryos compared with the control group. Furthermore, the mineral composition of sugar were determined. Nine mineral elements—potassium (K), calcium (Ca), sodium (Na), magnesium (Mg), iron (Fe), zinc (Zn), copper (Cu), phosphorus (P), and selenium (Se)—were analyzed. BS exhibited markedly higher concentrations of P, Ca, Fe, and Mg than RGS and WS, while selenium (detected at 50 mg/kg) was exclusively detected in BS. Intriguingly, RGS contained four-fold higher potassium levels than BS. Total polyphenol content, quantified by Folin-Ciocalteu assay, was 4.35 g/kg in BS and 1.53 g/kg in RGS, with no detectable polyphenols in WS.