The anti-nociceptive effects of ethanol extract of aerial parts of Schkuhria pinnata in mice

Developmental stages influence in vivo antimalarial activity of aerial part extracts of Schkuhria pinnata

ETHNOPHARMACOLOGICAL RELEVANCE

Malaria remains a dire health challenge, particularly in sub-Saharan Africa. In Uganda, it is the most ordinary condition in hospital admission and outpatient care. The country's meager health services compel malaria patients to use herbal remedies such as Schkuhria pinnata (Lam.) Kuntze ex Thell (Asteraceae). Although in vivo studies tested the antimalarial activity of S. pinnata extracts, plant developmental stages and their effect at different doses remain unknown.

AIM OF THE STUDY

This study aims to determine the effect of the plant developmental stage on the antimalarial activity of S. pinnata in mice and to document the acute oral toxicity profile.

METHODS

Seeds of S. pinnata were grown, and aerial parts of each developmental stage were harvested. Extraction was done by maceration in 70% methanol. The antimalarial activity was evaluated using chloroquine-sensitive Plasmodium berghei on swiss albino mice, in a chemosuppressive test, at 150, 350, and 700 mg/kg, p.o. Standard drugs used were artemether-lumefantrine (0.57 + 3.43) mg/kg and chloroquine (10 mg/kg) as positive controls. Distilled water at 1 mL/100g was used as a negative control. The Lorke method was adopted to determine the acute toxicity of extracts.

RESULTS

The flowering stage extract had a maximum suppression of parasitemia at 700 mg/kg (68.83 ± 4.49%). Extract at other developmental stages also significantly suppressed the parasitemia (in the ascending order) fruiting (50.71 ± 1.87%), budding (54.92 ± 7.56%), vegetative (55.39 ± 2.01%) compared to the negative control (24.7 ± 2.7%), p < 0.05. Extracts from all developmental stages increased survival time, with the flowering stage having the highest survival time at 20.33 ± 0.88 days. All extracts had an LD₅₀ of 2157 mg/kg, implying that extracts are safe at lower doses.

CONCLUSION

Together, our findings revealed that the S. pinnata extracts at the flowering stage had superior antimalarial activity compared to other plant developmental stages. Extracts from all developmental stages have demonstrated a dose-dependent suppression of malarial parasites and increased survival time with an LD₅₀ of 2157 mg/kg. Thus, for better antimalarial activity, local communities could consider harvesting S. pinnata at the flowering stage. Further studies are needed to isolate pure compounds from S. pinnata and determine their antimalarial activity.

Analgesic and Anti-Inflammatory Potential of Essential Oil of Eucalyptus camaldulensis Leaf: In Vivo and in Silico Studies

The objective of our present study is to scrutinize the analgesic and anti-inflammatory potentials of essential oil of Eucalyptus camaldulensis leaf using different in vivo assay models at doses of 100, 200, and 400 mg/kg body weight. Twenty chemical compounds, which were isolated from the leaves essential oil of E. camaldulensis, were docked using AutodockVina against cyclooxygenase 2, tumor necrosis factor-α, and interleukin-1β convertase to elucidate the analgesic and anti-inflammatory activity. The essential oil of E. camaldulensis exhibited noteworthy analgesic activities in the writhing test. In the tail immersion and hot-plate test, the essential oil significantly extended the latency period. The number of licks in the formalin-induced paw licking test was markedly reduced following essential oil administration. In addition, E. camaldulensis essential oil revealed notable anti-inflammatory responses in carrageenan-induced paw edema, xylene induced ear edema and cotton pellet induced granuloma methods. Among 20 compounds, 5 ( cis-sabinol, globulol, α-eudesmol, β-eudesmol, and γ-eudesmol) showed better binding for cyclooxygenase-2 while β-eudesmol exhibited higher affinity for TNFα than that of TNF-alpha-IN-1 and standard drug. In the case of interleukin 1β convertase, maximum affinity was shown by α-eudesmol than the synthetic drug belnacasan. Chemical components of the essential oil interacted with diverse amino acid residues which were similar to the natural substrate and standard drugs. In conclusion, E. camaldulensis essential oil can be an effective source of analgesic and anti-inflammatory treatment and additional modification and docking studies will be required to justify the efficiency of globulol, α-eudesmol, β-eudesmol, and γ-eudesmol.