Acute and Subchronic Toxicity Assessment of Conventional Soxhlet Cymbopogon citratus Leaves Extracts in Sprague-Dawley Rats

Background

In Ghana, Cymbopogon citratus leaves together with guava, pawpaw, and lime are processed into a decoction to treat fever. To encourage its usage, preclinical validation of the safety profile of the plant is required. The acute and subchronic toxicities of the conventional Soxhlet ethanolic Cymbopogon citratus leaves extract in Sprague-Dawley rats were investigated.

Methods

Pulverized Cymbopogon citratus leaves were extracted with 98% ethanol using the conventional Soxhlet extraction (CSE) method and dried. In the acute toxicity study, a single dose of 5000 mg/kg body weight was administered to six female Sprague-Dawley rats and 1 ml/100 g body weight normal saline to control (6) once, and signs of toxicity were observed every hour for the first 12 hr, 24 hr, and 48 hr through to 14 days. In the subchronic study, the treatment groups were administered 200 mg/kg, 600 mg/kg, and 1200 mg/kg, respectively, of the CSE C. citratus leaves extract for six weeks. Analyses were conducted on the blood, urine, and serum samples of the rats. Histopathological examination of the liver, heart, kidney, spleen, and lungs was carried out at termination. Analysis of variance (ANOVA) was performed to determine statistically significant differences between the test and control rats at P  <  0.05.

Results

The results revealed that there were no statistically significant differences (p  >  0.05) in the urinalysis and haematological analysis between control and test rats over the treatment period. Similarly, CSE C. citratus leaves extract did not induce any significant biochemical changes in the treatment group; however, there was a weight loss effect on the treated rats. There were no noticeable morphological changes in the heart, liver, spleen, lung, and kidney of the test rats compared to the control.

Conclusion

CSE ethanolic C. citratus leaves extract has a weight loss effect, and long-term administration of the extract may not cause any organ-specific toxicity to the consumers.

Assessment of the phytochemical composition and antimicrobial properties of Tapinanthus bangwensis leaves hosted by the branches of Persea americana

BACKGROUND

Medicinal plants represent a valuable source for new effective and safe antimicrobial drugs making them an alternative therapy. Existing antimicrobial agents are costly and mostly associated with possible side effects. The aim of the present study therefore, was to assess the antimicrobial property and phytochemical composition of hydroethanolic extract of Tapinanthus bangwensis leaves and its fractions.

METHOD

T. bangwensis leaves (harvested from its host plant, Persea americana) was extracted by cold maceration with 70% ethanol and further fractionated with different organic solvents using the solvent partitioning method to obtain the crude extract, petroleum ether, chloroform, ethyl acetate and the resulting aqueous fractions. The phytochemical constituents of the extracts were screened and quantified. Also, the TLC of the extracts were analyzed to serve as a fingerprint. Using the agar diffusion and broth dilution methods, the antimicrobial properties of the extracts were assessed.

RESULTS

The study showed that the hydroethanolic (70%) crude extract of T. bangwensis leaves and its fractions contain phenolic compounds, flavonoids, saponins, phytosterols and reducing sugars. The phytoconstituents were well extracted into the ethyl acetate fraction than the other fractions evidenced in the high levels (p < 0.0001) of saponins (66.47 ± 1.72% w/w), phenolic compounds (77.75 ± 1.06 mg/100 mg GAE) and flavonoids (44.34 ± 0.06 mg/100 mg QE) contents. From the antimicrobial studies, all the microorganisms tested exhibited varying degrees of susceptibility to the extracts with MIC values between 0.78 to 12.5 mg/mL. The crude extract of T. bangwensis leaves, its ethyl acetate and chloroform fractions also exhibited lethal antimicrobial activity with MLC between 6.25 to 50 mg/mL.

CONCLUSION

The crude extract of T. bangwensis leaves and its fractions demonstrated antimicrobial properties against Escherichia coli, Staphylococcus aureus, Staphylococcus saprophyticus and Candida albicans, thereby representing a potential source of natural antimicrobial agent. Further study is required to identify and isolate antimicrobial compounds from the plant for the development of the natural bioactive antimicrobial agents.

Prophylactic or therapeutic administration of Holarrhena floribunda hydro ethanol extract suppresses complete Freund's adjuvant-induced arthritis in Sprague-Dawley rats

Background

A hydro ethanol extract of the stem bark of Holarrhena floribunda (HFE) has been shown to be effective in the management of acute inflammation. This study was to evaluate usefulness of the extract for the management of chronic inflammation in a murine model.

Methods

Arthritis was induced in Sprague-Dawley rats using Complete Freund’s Adjuvant. Anti-arthritic effect of the extract was evaluated in prophylactic and therapeutic treatment models at doses of 50, 200 and 500 mg/kg. Parameters assessed included oedema, serology of inflammatory response, bone tissue histology and haematology. Data were analysed by ANOVA and Tukey’s multiple comparisons post hoc test.

Results

HFE at 50–500 mg/kg dose-dependently [P ≥ 0.0354 (prophylactic) and P ≥ 0.0001 (therapeutic) inhibited swelling of the injected paw upon prophylactic [≤ 81.26% (P < 0.0001) or therapeutic [≤ 67.92% (P < 0.01) administration — and prevented spread of arthritis to the contralateral paw. The inflammation alleviation activity was further demonstrated by decrease in arthritis score, radiologic score and erythrocyte sedimentation rate. HFE at all doses significantly reduced serum interleukin (IL)-1α (P < 0.0197), and 500 mg/kg HFE reduced IL-6 (P = 0.0032). In contrast, serum concentrations of IL-10, protein kinase A and cyclic adenosine monophosphate were enhanced (P ≤ 0.0436). HFE consistently showed better prophylactic than therapeutic activity.

Conclusion

HFE strongly suppressed Complete Freund’s Adjuvant-induced arthritis and modulated regulators of inflammation, including IL-1α, − 6 and − 10. Taken together, the data suggest that HFE has potential for use as an agent for modulation of the inflammatory response.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12950-022-00301-2.

Costus afer: A Systematic Review of Evidence-Based Data in support of Its Medicinal Relevance

Costus afer (C. afer) is a plant commonly known as ginger lily, spiral ginger, or bush cane. It is reportedly used in traditional medicine practice (TMP) to treat and manage many ailments including diabetes mellitus, stomach ache, arthritis, inflammation, and gout. These purported ethnomedicinal uses have triggered many research studies on the plant to amass scientific evidence. However, these research reports are scattered, and thus, this systematic review seeks to provide a comprehensive update on it covering its traditional uses, phytochemical and nutritional constituents, pharmacological activities, and toxicological effects. An online search was done using search engines such as Google Scholar, PubMed, and ScienceDirect from the period 1970 to 2019. The online search included the use of keywords, "Costus afer Ker-Gawl" or "Costus afer." The search revealed that the stem and leaves of the plant contain substantial amounts of micronutrients and macronutrients. The leaves, stem, rhizomes, and roots of C. afer contain several steroidal sapogenins, aferosides, dioscin, and paryphyllin C and flavonoid glycoside kaempferol-3-O-α-L-rhamnopyranoside. Experimental studies on various parts of the plant showed bioactivities such as antihyperglycemic, hepatocellular protection, cardioprotection, nephroprotection, testicular protection, CNS depressant, analgesic, antiarthritis, antibacterial, and antioxidant. Based on these evident data, it is concluded that the plant could be used as an alternative and complementary therapy for many oxidative stress-related diseases, provided further scientific studies on the toxicological and pharmacological aspects are carried out.

Two new phragmalin-type limonoids orthoesters from Entandrophragma candollei

Two new phragmalin-type limonoids orthoesters, encandollens A and B (1 and 2), were isolated from the stem barks of Entandrophragma candollei collected in Ghana. The structures of these compounds were elucidated on the basis of HR-ESI-MS, ¹H and ¹³C NMR, HSQC, HMBC, and ROESY data. Compound 1 was a rare C-15 enolic acyl phragmalin-type limonoid orthoester. Compounds 1 and 2 exhibited weak inhibitory effects on NO production in lipopolysaccharide (LPS)-induced RAW 264.7 cells.

Polyprenylated Tetraoxygenated Xanthones from the Roots of Hypericum monogynum and Their Neuroprotective Activities

Ten new polyprenylated tetraoxygenated xanthones, monogxanthones A-J (1-10), together with eight known analogues (4b, 11-17) were identified from the roots of Hypericum monogynum. The structures of these new polyprenylated xanthones (1-10), a class of compounds rarely found in plants of the genus Hypericum, were elucidated by the interpretation of their HRESIMS, 1D and 2D NMR, and electronic circular dichroism data. Compounds 1 and 2 exhibited neuroprotective effects against corticosterone (Cort)-induced lesions of PC12 cells at concentrations of 6.25, 12.50, and 25.00 μM, with cell viability greater than 75%, as well as inhibitory effects on nitric oxide production in lipopolysaccharide-induced BV2 microglia cells, with IC50 values of 7.47 ± 0.65 and 9.60 ± 0.12 μM, respectively. Collectively, these results shed new light on the potential of polyprenylated xanthones from the genus Hypericum in the development of antidepression therapies.

Limonoids with diverse frameworks from the stem bark of Entandrophragma angolense and their bioactivities

Entangolensins A–P (1–16), sixteen new limonoids with diverse frameworks, were obtained from the stem bark of Entandrophragma angolense.

Further C-15-acyl phragmalin derivatives from Chukrasia tabularis A. Juss

Relying on characteristic double UV absorptions (210 and 270 nm), sixteen phragmalins with three types of enolic acyl substituents at C-15 were isolated directly from EtOH extracts of the seeds of Chukrasia tabularis A. Juss. Eight of these compounds possessed a C-15-acetyl phragmalin skeleton, and the basic carbon skeleton and absolute configuration of one of these was determined by NMR and X-ray diffraction analysis, while the structures of the other phragmalins were determined via NMR, HR-MS, and CD spectra. Additionally, all of the isolates were tested for inhibition against lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW264.7 macrophages and cytotoxicity in SMMC-7721, MCF-7 and U2OS tumor cells.

Modulation of penile erection in rabbits by Mondia whitei: possible mechanism of action

Mondia whitei root was evaluated to validate its anecdotal use and determine its possible mode of action in the management of erectile dysfunction. Rabbits were administered with daily oral doses of 100-400 mg kg(-1) crude ethanolic extract of M. whitei and sildenafil (50 mg kg(-1)) as positive control for 6 weeks. Cavernosal tissue NOS activity and levels of NO and cGMP, and NOS and PDE protein expressions were investigated. The effect of the crude extract, chloroform and petroleum ether fractions in vitro on cavernosal tissue NOS activity and levels of NO and cGMP at 0.01 and 0.10 mg g(-1) tissue were also investigated. Results indicate that the crude extract increased NOS activity by 7% at 200 mg kg(-1) with corresponding increases in NO (88%) and cGMP (480%) levels. No significant changes in these measurements were observed with the 100 and 400 mg kg(-1) doses whilst sildenafil slightly reduced them (15.9-37.5%). NOS and PDE protein expressions in test animals were not different from controls. Pre-incubation of cavernosal tissue in vitro with the crude extract of M. whitei and its chloroform fraction markedly increased NOS activity (26-132%) and levels of NO (25%) and cGMP (50-400%) at 0.01 mg g(-1) tissue but these were reduced to near control levels when their concentrations were increased to 0.10 mg g(-1) tissue whilst the petroleum ether fraction had no effect. These findings suggest that M. whitei may influence erectile function through activation/stimulation of NOS with corresponding increases in tissue NO and cGMP levels and that certain chemical constituents present in the chloroform fraction may be responsible for biological activity.