Synergistic effects of Rhizoma Paridis and Rhizoma Curcuma longa on different animal tumor models.

Rhizoma Paridis saponins (RPS) with a good antitumor effect in clinical use showed low bioavailability and toxicity. Combination of Rhizoma Curcuma longa with RPS, which called LouHuang preparation (LH), not only overcame the RPS limitations but also improved its anticancer effect. The median lethal dose (LD₅₀) of LH in mice was 3410.9 mg/kg by oral acute toxicity test. LH relieved the inhibition of RPS on the gastric emptying (70.13 ± 4.80% vs. 49.12 ± 8.06%). As for the antitumor effect, the tumor weight/volume inhibition rate, tumor volume growth rate, and water/food efficiency ratio were calculated. LH had the highest inhibition ratio of 57.07 ± 2.97% for H22 model, 43.22 ± 0.72% for S180 model, and 46.8 ± 0.97% for EAC model, which were higher than RPS. Compared to ZiLongJin (ZLJ), a marked antitumor drug in China, LH also had the higher inhibition rate for tumor weight and tumor volume growth, which weaker than CTX. The water/food efficiency ratio reflected the difference of the quality life of the mice bearing tumor cells or not. CTX attenuated body weight gain and increased food efficiency ratio compared to control group. LH did not affect the body weight or water/food intake. The active part of LH was RPS and turmeric polysaccharides with the inhibition of 58% and 47% on H22 and S180 tumor models. The research provided theoretical and practical basis for LH application.