Analysis of the Anti-Cancer Effects of Cincau Extract (Premna oblongifolia Merr) and Other Types of Non-Digestible Fibre Using Faecal Fermentation Supernatants and Caco-2 Cells as a Model of the Human Colon

Abstract

Green cincau (Premna oblongifolia Merr) is an Indonesian food plant with a high dietary fibre content. Research has shown that dietary fibre mixtures may be more beneficial for colorectal cancer prevention than a single dietary fibre type. The aim of this study was to investigate the effects of green cincau extract on short chain fatty acid (SCFA) production in anaerobic batch cultures inoculated with human faecal slurries and to compare these to results obtained using different dietary fibre types (pectin, inulin, and cellulose), singly and in combination. Furthermore, fermentation supernatants (FSs) were evaluated in Caco-2 cells for their effect on cell viability, differentiation, and apoptosis. Cincau increased total SCFA concentration by increasing acetate and propionate, but not butyrate concentration. FSs from all dietary fibre sources, including cincau, reduced Caco-2 cell viability. However, the effects of all FSs on cell viability, cell differentiation, and apoptosis were not simply explainable by their butyrate content. In conclusion, products of fermentation of cincau extracts induced cell death, but further work is required to understand the mechanism of action. This study demonstrates for the first time that this Indonesian traditional source of dietary fibre may be protective against colorectal cancer.

Effects of Dietary Fibre from the Traditional Indonesian Food, Green Cincau (Premna oblongifolia Merr.) on Preneoplastic Lesions and Short Chain Fatty Acid Production in an Azoxymethane Rat Model of Colon Cancer

“…The cincau extract contained approximately 46% insoluble non-starch polysaccharides (NSPs) and 6% soluble NSPs [ 18 ], and this may explain why its effects on ACF formation mimicked those observed with rats fed insoluble cellulose as the main dietary fibre. Although gram for gram (when green cincau was used as the dietary fibre), only half the amount of insoluble cellulose would have been ingested by rats compared to the cellulose groups.…”

“…Green cincau leaves ( Premna oblongifolia Merr.) were collected from traditional farmers in Indonesia as described in Reference [ 18 ]. Fresh cincau leaves were dried at 50 °C (water content around 12%) and ground into fine powder before being imported into Australia using AQIS permit (IP07024278).…”

“…The mixture was then filtered, allowed to set at room temperature, and the resulting jelly-like extract was oven dried at 50 °C [ 15 ]. Compositional analysis of similar hot water extracts determined they contained 5.8% soluble non-starch polysaccharides (NSPs) and 46.3% insoluble NSPs [ 18 ]…”

“…As a dietary fibre, the extract also has laxative properties, and it effectively induces the growth of lactic acid bacteria in the colon [ 17 ]. Using an in vitro fermentation model, we recently demonstrated the ability of green cincau extracts to stimulate total short chain fatty acid (SFCA) production and to kill colon cancer cells [ 18 ]. As the green cincau leaf extract contains both high pectin levels and phenolic compounds which give it antioxidant activities, this recent study aimed to compare the efficacy of this traditional source of dietary fibre and antioxidant with other dietary fibre, antioxidant mixtures in preventing colon cancer using an in vivo rat model.…”

Immunomodulatory and Antioxidant Activity of Green Grass Jelly Leaf Extract (Cyclea barbata Miers.) In Vitro

“…Shrubs grass jelly (Premna parasitica Blume.) is known to have benefits as anticancer and human diets (Nurdin et al, 2017).…”