PHYTOCHEMICAL COMPOSITION AND ANTI- INFLAMMATORY POTENTIAL OF SWEET GUM (PAULLINIA PINNATA) AND MOUNTAIN THISTLE (ACANTHUS MONTANUS) LEAVES AFTER SIMULATED HUMAN GASTROINTESTINAL DIGESTION

Abstract

Acanthus montanus and Paullinia pinnata are shrub plants used in traditional medicine for the treatment of various diseases which includes mental disorders, abdominal pain, urinary diseases amongst others. However, the bioaccessibility and bioavailability of the compounds after consumption will most likely depend on their interactions with the digestive system. This study seeks to ascertain the in vitro antioxidant and anti-inflammatory activities of A. montanus and P. pinnata leaves after simulated human gastrointestinal digestion. Phytochemical screening was carried out to detect the different phytoconstituents present in the plants samples. Antioxidant assays; total flavonoid content, total phenolic content, 1,1, diphenyl-2-picrylhydrazyl radical scavenging ability, 2,2-azino-bis-93-ethylbenzthiazoline-6-sulphonic acid radical scavenging ability, hydroxyl radical scavenging ability, nitric oxide radical scavenging ability, iron chelation, reducing property and lipid peroxidation were carried out on both the enzyme digest and the ethanol water extract. Antioxidant enzyme assays; reduced glutathione enzyme, glutathione peroxidase, superoxide dismutase and catalase enzyme activity assays as well as anti-inflammatory assays such as heat-induced hemolysis, hypotonic solution-induced hemolysis, protein denaturation and antiproteinase activity assays were carried out on both the enzyme digest and the ethanol-water extract. Phytochemical screening result revealed the presence of alkaloids, tannins, terpenes, flavonoids and glycosides in A. montanus sample while also revealing the presence of alkaloids, steroids, flavonoids and glycosides in P. pinnata sample. The result revealed higher phenolic contents in the enzyme digest compared to the ethanol-water extract while flavonoids were more abundant in the ethanol-water extract compared to the enzyme digest. The antioxidant activities exhibited in the enzyme digest were potent than the ethanol-water extract. The antioxidant enzyme and anti-inflammatory activities of the enzyme digest were significantly higher than in the ethanol-water extract. This result implies that digestion improved the bioavailability and bio-accessibility of the phytoconstituents of these plants as evidenced by the increased antioxidant and anti-inflammatory activities of the enzyme digest comparable to those exerted in the ethanol-water extract. Hence, Acanthus montanus and Paullinia pinnata can be considered as good therapeutic intervention in the treatment of various diseases characterized by the oxidative stress and inflammation.