Research on the anti-aging activity of different mulberry leaf Products: Based on mulberry leaf powder and mulberry leaf extract

The concept of “whole foods” is becoming a hot research area. This study focused on the differences of in vivo metabolism and anti-aging activity between mulberry leaf powder (MLP) and mulberry leaf extract (MLE). For the metabolism experiment, involving male Kunming mice, plasma samples were collected at 1, 3 and 6 h after administration of saline, MLP or MLE. The MLP group exhibited controlled-release of polyphenols, compared to the MLE group. In the anti-aging experiment, D-gal was used to induce aging in female Kunming mice and the anti-aging effects of MLP, MLE, mulberry leaf post extraction residue (MLR), and MLE + MLR (MLM) were explored. Following an 8-week long-term intervention, all mulberry leaf product-treated groups showed higher T-AOC and lower MDA levels than the model control (MC) group (P < 0.05). While only MLP and MLM significantly enhanced plasma GSH-PX levels in aging mice (P = 0.001). The spatial learning and memory ability of aging animals was improved in each treatment group. In aging mice, the number of unique species, microbial community diversity, and Bacteroidota abundance decreased. The Firmicutes/Bacteroidetes ratio in the MC group increased by 1.87-fold compared to the NC group (P = 0.001). However, mulberry leaf products reversed these changes: MLP and MLE significantly lowered the Firmicutes/Bacteroidetes ratio in the MC group by 73.73 % and 68.66 %, respectively (P = 0.0001). At molecular level, mulberry leaf products not only significantly inhibited the phosphorylation of JNK but also markedly reduced the P-JNK/JNK ratio in liver of mice when comparing with the MC group (P < 0.05). The P-ERK/ERK ratio in liver of mice in the MC group was elevated 1.87-fold relative to the NC group, which could be diminished by treatment with MLP and MLM by 35.62 % and 56.28 %, respectively (P < 0.05). Overall, both MLP and MLE administration demonstrated efficacy in regulating intestinal microbiota, REDOX homeostasis, and behavioral performance of mice. However, in most instances, MLP exhibited a more pronounced effect compared to MLE, suggesting a synergistic anti-aging effects of dietary fiber and phenolic compounds present in mulberry leaves.