Indigenous Plants as Prebiotic Sources in Asia

Shahrul R. Sarbini
Department of Crop Science, Faculty of Agricultural and Food Sciences,
Universiti Putra Malaysia Bintulu Campus, Jalan Nyabau 97008,
Bintulu, Sarawak, MALAYSIA.

Corresponding email: shahrulrazid@upm.edu.my

ABSTRACT

To date, fructo-oligosaccharides, inulin, and galacto-oligosaccharides from plants are obvious source of prebiotics due to their numerous scientific demonstrations. Although most prebiotic are oligosaccharides, other forms such as polysaccharides in plant cell walls i.e. xylans, pectins and resistant starches are gaining popularity as prebiotic due to their indigestibility in the upper gastrointestinal, albeit selectively fermented by the colonic microbiota. The Asian region provides plentiful source of indigenous plants that may be a prebiotic. One interesting source is sago starch, from palm (Metroxylon sagu) indigenous to South-East Asia. In its native form called lemantak, it contains about 60 % resistant starch. Some in vitro and in vivo studies have demonstrated the ability of sago starch to increase numbers of Lactobacillus and Bifidobacterium. Studies on the effects of resistant starch on the glycemia index, insulin responses, and satiety have been continuously progressing, proving its role as a functional food. The Asian region also offers plentiful herbs and spices that are used as traditional medicines since ancient times. Most are due to their bioactive compounds i.e. polyphenols or flavonoids. Most polyphenols are of low bioavailability, where their influence on health may be either through intestinal absorption or interaction with colonic microbiota. A study observed thriving Bacteroidetes compared to Firmicutes upon intervention of polyphenols from black tea (Camellia sinensis) on simulated intestinal microbial ecosystem. Root of turmeric (Curcuma longa) is widely used as condiment in Asian food as well as a traditional remedy in Chinese and Indian Ayurvedic medicine. The curcuminoid are metabolised by colonic microbiota, modulating the bacterial population and their metabolic activity. The black pepper (Piper nigrum L.) is well-known for the presence of high bioactive compounds i.e. piperine that are anti-inflammatory, anti-oxidants and anti-bacterial, also containing up to 40 % dietary fibre, making them an interesting prebiotic candidate. Apart from terrestrial plant, aquatic plant such as seaweeds which are cultivated in East Asia and South-East Asia for carrageenan, can also be a potential prebiotic. The complex structure of this polysaccharide makes them resist enzymatic degradation, however fermented by colonic microbiota. The red seaweed (Kappaphycus alvarezii) showed significant increase of Bifidobacterium sp. number, acetate and propionate concentrations, during in vitro fermentations. The Asian region being the largest and most populous continent on earth, signify most diverse biological resource. It is very interesting to uncover the potential of the plants as emerging and novel prebiotic ingredients, adding value to these commodities.