Antitumor activity of Lycium barbarum polysaccharides with different molecular weights: an in vitro and in vivo study

Xiangliang Deng,Xiangling Li,Shuang Luo,Yongyan Zheng,Xia Luo,Lian Zhou

doi:10.1080/16546628.2017.1399770

Xiangliang Deng, Xiangling Li + Show 4 more

Open Access

https://doi.org/10.1080/16546628.2017.1399770

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Abstract

ABSTRACTThe antitumor activity of Lycium barbarum polysaccharide (LBP) has been reported, but the structure–bioactivity relationship has still not been fully elucidated. In this study, four water-soluble LBP fractions with serial different molecular weights (MWs) were separated from LBP, designated LBP-2, LBP-3, LBP-4, and LBP-5. After a characteristic analysis, the relationship between MW and antitumor activity of LBP was investigated both in vitro using murine hepatoma H22 cells and in vivo using H22 tumor-bearing mice. In vitro, the results showed that all the LBP fractions had significant inhibition on H22 cells, in which LBP-3 had the best activity. LBP-3 could induce apoptosis, mitochondrial membrane potential destruction, and S phase arrest in H22 cells. In vivo, the results showed that LBP-2, LBP-3, LBP-4, and LBP-5 could inhibit the tumor growth in H22 tumor-bearing mice by 18.18%, 37.97%, 9.09%, and 14.44%, respectively. However, only LBP-3 was able to decrease the tumor weight significantly in H22 tumor-bearing mice. Meanwhile, all the LBP fractions did not show significant toxicity to murine splenocytes, thymus, and spleen. Taken together, these results demonstrated that the antitumor activity of LBP was closely related to its MW, and LBP-3 with medium MW (40–350 kDa) was the main active fraction.

Highlights

Lycium barbarum polysaccharide (LBP), which is extracted from the fruit of a well-known Chinese herb Lycium barbarum, is found to have antitumor activity in recent years
The results showed that the total sugar contents of LBP-2, LBP-3, LBP-4, and LBP-5 were 66.88%, 54.47%, 56.53%, and 55.21%, respectively
Four water-soluble LBP fractions with serial different molecular weights (MWs) were isolated from LBP, in which we found that LBP-3 with medium MW had the highest antitumor activity in both in vitro and in vivo studies

Summary

Introduction

Lycium barbarum polysaccharide (LBP), which is extracted from the fruit of a well-known Chinese herb Lycium barbarum, is found to have antitumor activity in recent years. In vitro study results showed that LBP treatment inhibited tumor cells growth. Zhang [1] found that LBP treatment inhibited the growth of QGY7703 cells via induction of Sphase cell-cycle arrest and calcium-related apoptosis. Similar studies showed that LBP treatment could inhibit the growth of mouse colon cancer cells, human gastric cancer MGC-803, and SGC-7901 cells, and arrest the cell cycles at the G0/G1 or S phases [2,3]. The anticancer effects of LBP were demonstrated in tumor-bearing mice. Gan [4] revealed that a polysaccharide–protein complex from Lycium barbarum could significantly inhibit the growth of transplantable sarcoma S180 and improved the immune system in S180-bearing mice. Another study led by Zhang [5] found that LBP could obviously depress the death rate of H22 tumor-bearing mice and diminish gross tumor volume and weight

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