Phytochemical Profile, Acute Toxicity, Antioxidant and Anti-inflammatory Activity of Hydroethanolic Extracts from Odontonema strictum (Nees) Kuntze (Acanthaceae) Root and Stem

Background: The leaves of Odontonema strictum (Nees) Kuntze (Acanthaceae), a decorative plant native to Latin America, are used to treat hypertension in alternative medicine. However, the other parts of the plant have not yet been investigated for their antihypertensive properties. Aims: Our study aimed to investigate phytochemical groups with antihypertensive potential, antioxidant and anti-inflammatory properties, and the safety of using stems and roots hydroethanolic extracts.

Methodology: Phytochemical screening by HPTLC and determining flavonoids and total polyphenols were carried out. The antioxidant activity was evaluated using ABTS, FRAP, DPPH, and LPO methods. The inhibitory activity of Phospholipase A2 and 15-lipoxygenase was determined. Finally, acute oral toxicity was carried out on female mice NMRI.

Results: The hydroethanolic extracts of Odontonema strictum root (HE_ROS) and stem (HE_SOS) contain tannins, sterols, triterpenes, flavonoids, and saponosides. HE_SOS gave the highest levels of flavonoids (23.69±1.10 mg QE/g) and total phenolics (64.15±4.02 mg TAE/g. The two hydroethanolic extracts had antioxidant activity, with HE_ROS being the best. However, these activities were lower than Trolox (p<0.05). The extracts have a moderate inhibitory effect on 15-lipoxygenase and Phospholipase A2. Finally, HE_ROS and HE_SOS are practically non-toxic when administered once orally.

Conclusion: This study provided scientific data and could justify the use of Odontonema strictum in the treatment of hypertension.