Ranunculin, Protoanemonin, and Anemonin: Pharmacological and Chemical Perspectives.

Ranunculin, a glucoside, serves as a chemotaxonomic marker in Ranunculaceae plants. When these plants are damaged, an enzyme ß-glucosidase triggers the conversion of ranunculin into protoanemonin through hydrolysis. Subsequently, protoanemonin undergoes cyclodimerization to form anemonin. The inherent instability of ranunculin and the rapid dimerization of protoanemonin render them unsuitable for use in biological assays. Conversely, anemonin stands out as the optimal molecule for bioassays and demonstrates diverse biological properties, including anti-inflammatory, anti-infective, and anti-oxidant effects. Among these, anemonin exhibits the greatest promise in addressing conditions such as arthritis, cerebral ischemia, and ulcerative colitis. Its potential medical uses are enhanced by its capacity to inhibit nitric oxide synthesis and successfully counteract lipopolysaccharide-induced inflammation. This review describes the chemistry and biological properties of anemonin and its precursors, including discussions on extraction, isolation, synthesis, and investigations into bioactivity and pharmacokinetics.

In vitro and in vivo antitrypanosomal activity of the fresh leaves of Ranunculus Multifidus Forsk and its major compound anemonin against Trypanosoma congolense field isolate.

BACKGROUND: Animal trypanosomiasis is a major livestock problem due to its socioeconomic impacts in tropical countries. Currently used trypanocides are toxic, expensive, and the parasites have developed resistance to the existing drugs, which calls for an urgent need of new effective and safe chemotherapeutic agents from alternative sources such as medicinal plants. In Ethiopian traditional medicine fresh leaves of Ranunculus multifidus Forsk, are used for the treatment of animal trypanosomiasis. The present study aimed to evaluate the antitrypanosomal activity of the fresh leaves of R. multifidus and its major compound anemonin against Trypanosoma congolense field isolate. METHODS: Fresh leaves of R. multifidus were extracted by maceration with 80% methanol and hydro-distillation to obtain the corresponding extracts. Anemonin was isolated from the hydro-distilled extract by preparative TLC. For the in vitro assay, 0.1, 0.4, 2 and 4 mg/ml of the test substances were incubated with parasites and cessation or drop in motility of the parasites was monitored for a total duration of 1 h. In the in vivo assay, the test substances were administered intraperitoneally daily for 7 days to mice infected with Trypanosoma congolense. Diminazene aceturate and 1% dimethylsulfoxide (DMSO) were used as positive and negative controls, respectively. RESULTS: Both extracts showed antitrypanosomal activity although the hydro-distilled extract demonstrated superior activity compared to the hydroalcoholic extract. At a concentration of 4 mg/ml, the hydro-distilled extract drastically reduced motility of trypanosomes within 20 min. Similarly, anemonin at the same concentration completely immobilized trypanosomes within 5 min of incubation, while diminazene aceturate (28.00 mg/kg/day) immobilized the parasites within 10 min. In the in vivo antitrypanosomal assay, anemonin eliminates parasites at all the tested doses (8.75, 17.00 and 35.00 mg/kg/day) and prevented relapse, while in diminazene aceturate-treated mice the parasites reappeared on days 12 to 14. CONCLUSIONS: The current study demonstrated that the fresh leaves of R. multifidus possess genuine antitrypanosomal activity supporting the use of the plant for the treatment of animal trypanosomiasis in traditional medicine. Furthermore, anemonin appears to be responsible for the activity suggesting its potential as a scaffold for the development of safe and cost effective antitrypanosomal agent.

Antinociceptive and antiinflammatory activities of crude leave extract and solvent fractions of Commelina latifolia Hochst. ex C.B.Clarke (Commelinaceae) leaves in murine model.

Ethnopharmacological relevance: In the past, Ethiopian traditional medicine employed the leaves of the native Commelina latifolia Hochst. ex C.B. Clarke plant to treat wounds, pain, and malaria. Aim of the study: The crude extract and solvent fractions of C. latifolia Hochst. ex C.B. Clarke leaves were examined in the present investigation to determine their ability to have an antiinflammatory effect and provide an antinociceptive effect in animal models. Materials and methods: The leaves of C. latifolia were extracted with 80% methanol, and the CL crude extract was further fractionated with chloroform, pure methanol, and distilled water. The carrageenan-induced paw edema model was used to test the extracts' ability to reduce inflammation. The hotplate model and the acetic acid-induced writhing test on rodents were used to test the extracts' potential antinociceptive effect to reduce pain. Results: Inflammation was decreased by 64.59% with CL crude extract (400 mg/kg); 56.34% (400 mg/kg) of methanol fraction, 64.59% of aqueous fraction (400 mg/kg), and 38.27% of chloroform fraction in the carrageenan-induced inflammatory model. All extracts demonstrated a considerable lengthening of the nociception reaction time in the hot plate test, with a maximum antinociceptive effect of 78.98% (crude extract) and 71.65% (solvent fractions). At a dosage of 400 mg/kg, the natural C. latifolia crude extract and aqueous fraction demonstrated considerable antinociceptive effects against acetylsalicylic acid (ASA) during the writhing test (48.83% and 45.37than%, respectively). The current findings support Ethiopia's traditional user's assertions that the herb can alleviate inflammation and pain.

Antimalarial activity of the 80%methanol extract and solvent fractions of Cucumis ficifolius A. rich roots against Plasmodium berghei in mice.

Ethnopharmacological relevance: Malaria is still a known health threat, especially in parts of sub-Saharan Africa. It is one of the frequently mentioned issues with hospital admission and outpatient care in Ethiopia. Cucumis ficifolius A. Rich roots are historically used in Ethiopia to treat meningitis, inflammation, and malaria. However, the antimalarial activity of this plant has not been scientifically studied so far. Aim of the study: This study aimed to determine the in vivo antimalarial activity of 80% methanol extract and solvent fractions of the roots of Cucumis ficifolius against Plasmodium berghei infection in mice. Methods: The in vivo antimalarial activity of the 80% methanol extract and solvent fractions of Cucumis ficifolius A. Rich was evaluated by standard chemo suppressive, curative and repository tests using Plasmodium berghei (ANKA strain) in Swiss albino mice at doses of 100, 200 and 400 mg/kg/day. The level of parasitemia, survival time, variation in weight, rectal temperature, and packed cell volume of mice were determined to establish the activity of the extracts. Result: The 80% methanol extract of Cucumis ficifolius A. Rich roots had a promising suppression of parasitemia at 400 mg/kg with a chemosuppression value of 65.21 ± 1.20%. Among the solvent fractions, the chloroform fraction showed the highest antimalarial activity in the four-day suppressive test with a chemosuppression value of 55.9 ± 0.28%, followed by the n-butanol (42.9 ± 0.24%), and aqueous (40.57 ± 0.52%) fractions at a dose of 400 mg/kg. The highest survival times were observed with crude extract (15.4 ± 0.24 days) at 400 mg/kg, and chloroform fraction (13.4 + 0.24 days), though all extracts increased survival time. Conclusion: The findings of the present study collectively indicate the root extract of Cucumis ficifolius has a promising antiplasmodial activity which substantiates the traditional claim of the plant.

In Vitro Antileishmanial and Antischistosomal Activities of Anemonin Isolated from the Fresh Leaves of Ranunculus multifidus Forsk.

Leishmaniasis and schistosomiasis are neglected tropical diseases (NTDs) infecting the world's poorest populations. Effectiveness of the current antileishmanial and antischistosomal therapies are significantly declining, which calls for an urgent need of new effective and safe drugs. In Ethiopia fresh leaves of Ranunculus multifidus Forsk. are traditionally used for the treatment of various ailments including leishmaniasis and eradication of intestinal worms. In the current study, anemonin isolated from the fresh leaves of R. multifidus was assessed for its in vitro antileishmanial and antischistosomal activities. Anemonin was isolated from the hydro-distilled extract of the leaves of R. multifidus. Antileishmanial activity was assessed on clinical isolates of the promastigote and amastigote forms of Leishmania aethiopica and L. donovani clinical isolates. Resazurin reduction assay was used to determine antipromastigote activity, while macrophages were employed for antiamastigote and cytotoxicity assays. Antischistosomal assays were performed against adult Schistosoma mansoni and newly transformed schistosomules (NTS). Anemonin displayed significant antileishmanial activity with IC50 values of 1.33 nM and 1.58 nM against promastigotes and 1.24 nM and 1.91 nM against amastigotes of L. aethiopica and L. donovani, respectively. It also showed moderate activity against adult S. mansoni and NTS (49% activity against adult S. mansoni at 10 µM and 41% activity against NTS at 1 µM). The results obtained in this investigation indicate that anemonin has the potential to be used as a template for designing novel antileishmanial and antischistosomal pharmacophores.

In Vivo Antimalarial Activity of Leaf Extracts and a Major Compound Isolated from Ranunculus multifidus Forsk.

The leaves of Ranunculus multifidus Forsk. are traditionally used for the treatment of malaria in several African countries. In the present study, 80% methanol (RM-M) and hydrodistilled (RM-H) extracts of fresh leaves from R. multifidus and its major constituent anemonin were tested for their in vivo antimalarial activity against Plasmodium berghei in mice. Anemonin was also tested for its in vitro antimycobacterial activity against Mycobacterium smegmatis and M. abscessus in a microbroth dilution assay, and bacterial growth was analyzed by OD measurement. The isolation of anemonin from RM-H was carried out using preparative thin layer chromatography (PTLC). The chemical structures of anemonin and its hydrolysis product were elucidated using spectroscopic methods (HR-MS; 1D and 2D-NMR). Results of the study revealed that both RM-M and RM-H were active against P. berghei in mice, although the latter demonstrated superior activity (p < 0.001), as compared to the former. At a dose of 35.00 mg/kg/day, RM-H demonstrated a chemosuppression value of 70% in a 4-day suppressive test. In a 4-day suppressive, Rane's and prophylactic antimalarial tests, anemonin showed median effective doses (ED50s) of 2.17, 2.78 and 2.70 µM, respectively. However, anemonin did not inhibit the growth of M. smegmatis and M. abscessus.