In Vitro and In Silico Antidiabetic and Antimicrobial Evaluation of Constituents from Kickxia ramosissima (Nanorrhinum ramosissimum)

Background and Aims:Kickxia ramosissima (Wall.) Janch (or Nanorrhinum ramosissimum (Wall.) Betsche is a well-known medicinal plant in Pakistan that is traditionally used in diabetic and inflammatory conditions. Because little information is available on its phytochemical composition, a range of constituents were isolated and evaluated in vitro in assays related to the traditional use.

Methods: Dried whole plant material was extracted and chromatographically fractionated. Isolated constituents were evaluated in silico and in vitro in assays related to the traditional use against diabetes (inhibition of α-glucosidase activity; inhibition of advanced glycation endproducts) and in inflammatory conditions (inhibition of AAPH induced linoleic acid peroxidation, inhibition of 15-LOX, antimicrobial activity).

Results: Phytochemical analysis of the extracts and fractions led to isolation of 7 compounds, including the iridoids kickxiasine (being a new compound), mussaenosidic acid, mussaenoside and linarioside; the flavonoids pectolinarigenin and pectolinarin; and 4-hydroxy-benzoic acid methyl ester. The iridoids showed weak antiglycation activity. The flavonoids, however, showed interesting results as pectolinarigenin was highly active compared to pectolinarin. In the α-glucosidase inhibition assay, only weak activity was observed for the iridoids. However, the flavonoid pectolinarigenin showed good activity, followed by pectolinarin. In the 15-LOX experiment, moderate inhibition was recorded for most compounds, the iridoids mussaenosidic acid and mussaenoside being the most active. In the AAPH assay, weak or no inhibition was recorded for all compounds. The in silico assays for the α-glucosidase and 15-LOX assays confirmed the results of respective in vitro assays. Pectolinarigenin showed moderate antimicrobial activity against Staphylococcus aureus, Plasmodium falciparum K1, and Trypanosoma cruzi, but it was not cytotoxic on a human MRC-5 cell line.

Conclusion: Our findings may in part contribute to explain the traditional use of K. ramosissima.

Antipyretic, analgesic and anti-inflammatory effects of Kickxia ramosissima

ETHNOPHARMACOLOGICAL RELEVANCE

Branched cancerwort, Kickxia ramosissima (Wall.) Janchen (Scrophulariaceae) is traditionally used for the treatment of inflammatory disorders such as rheumatism, diabetes, jaundice and for activation of immune system. Local communities also used this plant for the treatment of spleen enlargement, as febrifuge and in dysmenorrhea. In this investigation antipyretic, analgesic and anti-inflammatory effects of K. ramosissima have been evaluated.

METHODS

Dried powder of the whole plant of K. ramosissima was extracted with methanol (KRM) and partitioned with solvents to obtain the n-hexane (KRH), chloroform (KRC), ethyl acetate (KRE), n-butanol (KRB) and the residual aqueous (KRA) fraction. KRM and the derived fractions were analyzed for the phytochemical constituents, yeast induced pyrexia, analgesic and anti-inflammatory activities by using carrageenan and Freunds' complete adjuvant-induced paw edema model in rat. On account of appreciable effects of KRM in the aforesaid models, KRM was subjected to the carrageenan induced air pouch model in rat. The exudate of air pouch was analyzed for the count of neutrophils, monocytes, lymphocytes and WBCs and for the estimation of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), nitric oxide (NO) and prostaglandin (PGE2).

RESULTS

Phytochemical investigation of KRM indicated the existence of tannins, flavonoids, alkaloids, coumarins, cardiac glycosides, saponins, terpenoids and phlobatannins. Maximum concentration of total phenolic was determined in KRB followed by KRM while reverse was true for total flavonoids contents. KRM (200mg/kg) distinctly decreased the rectal temperature in yeast induced pyrexia comparable to standard, paracetamol. Pain sensation was effectively inhibited at 200mg/kg p.o. of KRM and KRB as manifested by a decrease (P<0.001) in count of writhing induced with acetic acid and increase of latency time in hot plate. Anti-inflammatory effects of KRM were evident and edema formation induced with carrageenan and Freunds' complete adjuvant-induced paw edema in rat was significantly (P<0.001) inhibited. Count of neutrophils, monocytes, lymphocytes, and WBCs along with inflammatory mediators; IL-6, NO, TNF-α and PGE2 was significantly (P<0.001) decreased in subcutaneous air pouch exudate with KRM. HPLC analysis of KRM indicated the presence of gallic acid, caffeic acid, rutin, catechin and myricetin.

CONCLUSION

The results suggested the anti-inflammatory effects of KRM in inflammation related disorders, might be attributed by the presence of active phytoconstituents; flavonoids, saponins and terpenoids.