Abstract: In this study, the contents of total sugars, crude polysaccharides, total phenols and total flavonoids in the aqueous and ethanol extracts of pine pollen, the large molecules isolated from the aqueous extract (> 5 kDa), and the small molecules isolated from the ethanol extract (< 5 kDa) were determined, and their protective effects on ovarian injury induced by cyclophosphamide in SD rats were explored. The results showed that compared with the model group, the ethanol extract and its small molecule fraction effectively increased the ovarian index, the number of mature follicles, the ovarian antioxidant enzyme activities total antioxidant capacity (T-AOC), catalase (CAT), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) (by 16.03%, 25.81%; 138.42%, 237.09%; 104.31%, 109.90%; and 91.62%, 120.63%, respectively), and anti-apoptotic protein expression. In addition, they inhibited atretic follicles and ovarian lipid oxidation, as evidenced by a decrease in the content of malondialdehyde (MDA) by 53.42% and 48.43%, respectively; the effect was more pronounced than that of the aqueous extract and its large molecule fraction, while the aqueous extract and its large molecule fraction could protect the ovaries by reducing the pro-inflammatory cytokine tumor necrosis factor-α (TNF-α) activity. This study provides a theoretical basis for further investigation of the mechanism of the ovario-protective effect of pine pollen and also provides technical guidance for the development of new products based on pine pollen extracts.

Key words: pine pollen; aqueous extracts; alcoholic extracts; aqueous soluble large molecules; ethanol soluble small molecules; ovarian injury