Kansuiphorin C and Kansuinin A ameliorate malignant ascites by modulating gut microbiota and related metabolic functions

Ethnopharmacological relevance: Euphorbia kansui is a toxic Chinese herbal medicine and exhibits promising treatment to the malignant ascites (MA) in its traditional use. Ingenane-type and jastrophane-type diterpenes are demonstrated to be responsible for the toxicity and efficacy of kansui. Two representative compounds, kansuiphorin C (KPC) and kansuinin A (KA) in each type were proved to effectively reduce the ascites. The biological and toxicological effects are closely associated with the gastrointestinal tract, but the possible mechanism and related metabolic functions of KPC and KA treating MA through modulating the gut microbiota remain unclear.

Aim of the study: To investigate the possible mechanism and related metabolism of KPC and KA ameliorating malignant ascites through modulating gut microbiota.

Materials and methods: MA rats and normal rats were divided into different groups and administrated with KPC, KA, and positive drug, respectively. 16S rDNA gene sequencing and metagenomes analysis combined with the quantification of short-chain fatty acids of feces were performed to reflect the modulation of gut microbiota. Then, the metabolites of KPC and KA in rat feces under the normal and pathological circumstances were detected by ultra-fast liquid chromatography coupled with MS/MS detector (UFLC-MS/MS) to explore the in-vivo Bacterial biotransformation.

Results: KPC and KA were modulatory compounds for gut microbiota. The richness of Lactobacillus and the decreased abundance of Helicobacter involved in the carbohydrate metabolism and amino acid metabolism could be responsible for their prohibitory effects on malignant ascites. KPC exhibited stronger modulation of gut microbiota through making the abundance of Helicobacter about 3.5 times lower than KA. Besides, in-vivo microbial biotransformation of KPC and KA contained oxidation, hydrolysis, dehydration, and methylation to form metabolites of lower polarity. Besides, at the dosage of 10 mg kg^-1, the toxicity of both compounds had weaker influences on the gut microbiota of normal rats.

Conclusion: KPC and KA could ameliorate malignant ascites by modulating gut microbiota mainly containing the increase of Lactobacillus and the decrease of Helicobacter and related carbohydrate and amino acid metabolism, providing a basis for their promising clinical usage.