Investigation of the antinociceptive and anti-inflammatory properties of Heteromorpha arborescens (Apiaceae)

Cytotoxicity, Anti-Obesity and Anti-Diabetic Activities of Heteromorpha arborescens (Spreng.) Cham Leaves

This study investigated the cytotoxicity, anti-obesity and anti-diabetic potentials of blanched, aqueous and ethanol extracts of Heteromorpha arborescens (Spreng.) Cham leaves. The results revealed that both ethanol and aqueous extracts exhibited considerable inhibition against α-glucosidase (IC50 of 627.29 ± 4.62 µg/mL and 576.46 ± 3.21 µg/mL respectively), while the blanched extract showed weak α-glucosidase inhibition (IC50; 855.38 ± 4.29 µg/mL) and the aqueous extract showed the best α-amylase inhibition (IC50; 583.74 ± 5.87 µg/mL). However, weak α-amylase inhibition was observed in the ethanol (IC50; 724.60 ± 4.33 µg/mL) and blanched extracts (IC50; 791.63 ± 3.76 µg/mL). The toxicity of the extracts is indicated by LC50 values as 154.75 µg/mL, 125 µg/mL and 90.58 µg/mL for ethanol, aqueous and blanched extracts respectively, indicating the blanched extract to be the most toxic. Moderate glucose utilization in both C3A and L6 cells was also observed for the aqueous and ethanol extracts which may be attributed to the relatively lower toxicity levels present. However, glucose utilization was very weak for the blanched extract, which may be due to higher level of cytotoxicity it possessed. Relatively weaker lipase inhibition was observed for the ethanol (IC50; 699.3 ± 1.33 µg/mL), aqueous (IC50; 811.52 ± 3.52 µg/mL) and blanched extracts (IC50; 1152.7 ± 4.61 µg/mL) compared to orlistat (IC50; 56.88 ± 0.11 µg/mL). However, there was no reasonable reduction in lipid accumulation observed in all the extract treated cells. These observations suggest that ethanol and aqueous extracts of H. arborescens leaf are promising as new agents for the treatment of diabetes and its acclaimed anti-obesity potentials are likely due to its lipase, α-amylase and α-glucosidase inhibition.

Assessment of the phytochemical, antioxidant and antibacterial activities of Heteromorpha arborescens (Spreng.) Cham & Schltdl. leaf extracts

Background: Heteromorpha arborescens (Spreng.) Cham. and Schltdl (Apiaceae) is widely used traditionally for the treatment of a wide range of diseases in Southern and Eastern Africa. Although previous studies have reported the biological activities of hexane, ethyl acetate and methanol extracts of H. arborescens leaves, there is no scientific information on the phytochemical contents, antioxidant and antibacterial activities of acetone, ethanol, aqueous and blanched extracts. This study is therefore aimed to investigate and compare the phytochemical contents, antioxidant and antibacterial activities of acetone, ethanol, aqueous and blanched extracts of H. arborescens leaves. Methods: Phytochemical analysis for the total phenolic, flavonoid, proanthocyanidin, alkaloid and saponin contents of all the fractions were determined by spectroscopic methods, while the free radical scavenging potential of the extracts were evaluated using DPPH, ABTS radical scavenging and total antioxidant capacity assays. Micro dilution method was used to determine the Minimum Inhibitory Concentrations (MIC) of H. arborescens leaf extracts against Bacillus pumilus, Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae. Results: Total phenol content of the extracts ranged between 15.10 mg GAE/g- 42.50 mg GAE/g, proanthocyanidin was 459-8402.1 mg QE/g, and flavonoid content of 109.24-235.79 mg QE/g. In addition, alkaloids (5.59%) and saponins (23.33%) were present in significant amounts. Based on the IC ₅₀ values, the ethanol extract exhibited the highest total antioxidant activity (0.013 mg/mL) with highest inhibition against DPPH and ABTS radicals (0.06 and 0.049 mg/mL respectively). Considerable antibacterial activities were observed in the acetone, ethanol and blanched extracts with MIC values ranging from 1.563-12.5 mg/mL; however, the aqueous extract was inactive against all the bacteria strains. Conclusion: The study suggests that H. arborescens leaves could be a valuable source of bioactive compounds. Although the blanching process significantly decreased polyphenolic contents and antioxidant activities of the extracts, it increased the antibacterial compounds.

Semisynthesis of Derivatives of Oleanolic Acid from Syzygium aromaticum and Their Antinociceptive and Anti-Inflammatory Properties

Oleanolic acid is a pentacyclic triterpenoid compound widely found in plants and well known for its medicinal properties. Oleanolic acid (OA) was isolated from the ethyl acetate extract of Syzygium aromaticum flower buds. Semisynthesis afforded both acetate and ester derivatives. The derived compounds were monitored with thin layer chromatography and confirmed with nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry (MS), Fourier infrared (FT-IR) spectroscopy, and melting point (Mp). All these compounds were evaluated for their analgesic and anti-inflammatory properties at a dose of 40 mg/kg. Significant analgesic and anti-inflammatory effects were noted for all OA-derived compounds. In the formalin-induced pain test, the derivatives showed better analgesic effects compared to their precursor, whereas, in the tale flick test, oleanolic acid proved to be superior in analgesic effects compared to all its derivatives with the exception of the acetyl derivative. Acute inflammatory tests showed that acetyl derivatives possessed better anti-inflammatory activity compared to the other compounds. In conclusion, semisynthesis of oleanolic acid yielded several derivatives with improved solubility and enhanced analgesic and anti-inflammatory properties.

Antinociceptive and Anti-Inflammatory Activities of Telfairia occidentalis Hydroethanolic Leaf Extract (Cucurbitaceae)

Telfairia occidentalis (Cucurbitaceae) is a tropical vine grown in West Africa as a leaf vegetable and for its edible seeds. The plant is noted to have healing properties. It is used as a blood tonic to revive weak/ill individuals and its use by sickle cell patients has been documented. In this study, the antinociceptive activity of the hydroethanolic leaf extract of Telfairia occidentalis (TO) was evaluated using the acetic acid-induced writhing, formalin, tail clip, and hot plate tests in mice. The carrageenan- and egg albumin-induced rat paw edema tests were used to evaluate the anti-inflammatory action. The extract (50-400 mg/kg, p.o.) produced significant (P<.05) dose-dependent inhibition of pain response elicited by acetic acid and formalin while also increasing the nociceptive reaction latency in the tail clip and hot plate tests. In respect of anti-inflammatory activity, the extract elicited significant (P<.05) time and dose-dependent inhibition of edema development in the carrageenan and egg albumin tests. Peak effects of TO in the models were generally comparable with the effects of the standard drugs (acetylsalicylic acid, morphine, indomethacin, and chlorpheniramine) used. Phytochemical screening of the extract revealed the presence of tannins, saponins, phlobatannins, and anthraquinones. The extract did not produce any mortality and visible signs of delayed toxicity when administered orally up to 2000 mg/kg. The LD50 (i.p.) was estimated to be 4073.80 mg/kg. The results obtained in this study suggest that TO possesses antinociceptive and anti-inflammatory activities possibly mediated through peripheral and central mechanisms involving inhibition of release and/or actions of vasoactive substances and prostaglandins.