Two Limonoids, Khayalenoids A and B with an Unprecedented 8-Oxa-tricyclo[4.3.2.02,7]undecane Motif, from Khaya senegalensis

Mexicanolide limonoids from the seeds of Khaya ivorensis with antimicrobial activity

The methanol extract of the seeds of Khaya ivorensis afforded two new mexicanolide limonoids, ivorensines A and B (1 and 2), together with one known compound, ruageanin D (3). The structures of the isolated compounds were established based on 1 D and 2 D (¹H-¹H COSY, HMQC, and HMBC) NMR spectroscopy, in addition to high resolution mass spectrometry. The isolated limonoids were tested in vitro for antimicrobial potentials against 5 pathogenic microorganisms. As a result, compounds 1-3 exhibited antimicrobial activity against the tested Gram negative bacteria at the minimum inhibitory concentration values less than 50 μg/ml.

Antimicrobial mexicanolide limonoids from the seeds of Khaya senegalensis

Three new mexicanolide limonoids were obtained from the 90% ethanol extract of the seeds of Khaya senegalensis. Their structures were elucidated as senegalenines A-C (1-3) by analysing their 1D/2D NMR and MS spectroscopic analysis. In addition, the isolated limonoids were tested in vitro for antimicrobial potentials against 5 pathogenic microorganisms. Consequently, compounds 1-3 exhibited antimicrobial activity against the tested Gram negative bacteria at the minimum inhibitory concentration values less than 40 μg/ml.

Spirotrichilins A and B: Two Rearranged Spirocyclic Limonoids from Trichilia connaroides

Spirotrichilins A (1) and B (2), two novel limonoids with an unprecedented spiro[cyclopenta[b]furan-2,1'-cyclopentan] ring system in A/B/C rings, were isolated from the fruits of trichilia connaroides. Their planar structures and absolute configurations were established based on 1D-, 2D-NMR data, electronic circular dichroism (ECD) exciton chirality method and time-dependent density functional theory (TDDFT)/ECD calculation. A benzilic acid-like rearrangement in ring A was proposed as the key step in the plausible biogenetic pathway of 1 and 2.

Trichiconlides A and B: two novel limonoids from the fruits of Trichilia connaroides

Trichiconlides A (1) and B (2), two novel limonoids, were isolated from the fruits of Trichilia connaroides. Compound 1 is a novel limonoid with a highly rearranged A/B ring system and an intact D ring, which formed an unprecedented 5/6/5/6/5 carbon skeleton. Trichiconlide B (2) possesses a 10-oxatricyclo[3.3.1.(3,8)]decane core and formed a cage-like structure located between rings A and C. Their structures and absolute configurations were elucidated by spectroscopic methods, single crystal X-ray diffraction, the ECD exciton chirality method and TDDFT/ECD calculations. 1 showed a moderate inhibitory effect on nitric oxide (NO) production.

Mexicanolide limonoids with in vitro neuroprotective activities from seeds of Khaya senegalensis

Fourteen new mexicanolide-type limonoids khasenegasins A–N (1–14) were isolated from the seeds of Khaya senegalensis, and bioactivity scan indicated that these mexicanolide-type limonoids displayed neuroprotective activities.

An overview on chemical aspects and potential health benefits of limonoids and their derivatives

Limonoids are heavily oxygenated, modified triterpenes dominant in Meliaceae and Rutaceae plant families. The term 'limonoid' is derived from limonin, which was first identified as the bitter constituent of Citrus seeds in 1841. This group of secondary metabolites exhibits a wide range of biological properties, including anticancer, antibacterial, antifungal, antimalarial, and antiviral activities. Significant progress on the role of limonoids as promising candidates for cancer chemoprevention and/or therapy has been achieved in particular in recent years. The aim of this review article is to discuss the recent developments on limonoids chemical aspects and biological activities with the relationship between structure and activity, supporting the new possibilities for the medicinal and/or nutraceutical use of these compounds.

Phenolics-rich fraction of Khaya senegalensis stem bark: antitrypanosomal activity and amelioration of some parasite-induced pathological changes

CONTEXT

The stem bark of Khaya senegalensis A. Juss (Meliaceae) is currently used for the treatment of trypanosomiasis by traditional practitioners in Nigeria.

OBJECTIVES

The present study investigated the anti-Trypanosoma brucei brucei activity of phenolics-rich fraction of K. senegalensis (pfks) and its ameliorative effects on trypanosome-induced pathological changes.

MATERIALS AND METHODS

The fraction was initially analyzed by gas chromatography-mass spectrometry (GC-MS). A 60 min time course experiment was conducted with various concentrations of the fraction using a 96-well microtiter plate technique and was further used to treat T. brucei infected rats at 100, 200 and 300 mg/kg body weight (BW). Indices of anemia as well as hepatic and renal functions were analyzed in all experimental animals at the end of the experiment.

RESULTS

The GC-MS analysis of the pfks revealed that the most abundant phytochemicals are phloroglucinol (40.56%) and 3,4-(dihydroxyphenyl) acetic acid (41.76%). The fraction showed a concentration dependent in vitro antitrypanosomal activity. Interestingly, the fraction completely eliminated the parasites from the bloodstream of infected rats without relapse during the experimental period at the dose of 300 mg/kg BW and also kept the parasites consistently lower at 100 and 200 mg/kg BW than that was recorded in the untreated infected rats. Furthermore, the severity of T. brucei-induced anemia and hepatic damage was significantly (p < 0.05) ameliorated in the 300 mg/kg BW treatment group whereas the parasite-induced renal damage was significantly (p < 0.05) ameliorated in all treatment groups.

CONCLUSION

Data from this study may suggest that phenolics play an important role in the antitrypanosomal activity of K. senegalensis.

Khayseneganins A-H, limonoids from Khaya senegalensis

Eight new limonoids, khayseneganins A-H (1-8), and 31 known limonoids were isolated from the leaves and twigs of Khaya senegalensis. The structures of the new compounds were elucidated by 2D-NMR spectroscopy and mass spectrometry, and the absolute configuration of 1 was determined by the CD exciton chirality method. Compounds 9, 10, 12, and 15 showed antimicrobial activities against Pseudomonas aeruginosa, MRSA 92(#), and MRSA 98(#), all with a MIC value of 12.5 μg/mL.

Limonoids from the fruits of Aphanamixis polystachya (Meliaceae) and their biological activities

Seven new prieurianin-type limonoids, aphapolynins C-I (1-7), and a new aphanamolide-type limonoid, aphanamolide B (8), along with seventeen known compounds, were isolated from the fruits of Aphanamixis polystachya. The structures of these compounds were established on the basis of spectroscopic studies. The absolute configurations were determined by combination of electronic circular dichroism (ECD) calculation, CD exciton chirality method, and single crystal X-ray diffraction. All these isolates were evaluated for their cytotoxicities against three human cancer cell lines, for their inhibitory effects on lipopolysaccharide (LPS) induced RAW264.7 murine macrophages, and for their fungicidal, herbicidal, and insecticidal activities. Compounds 1, 14, 16, and 17 exhibited significant fungicidal activities; 1 and 25 in particular showed good insecticidal activities. The α,β-unsaturated lactone and 14,15-epoxy ring moieties were essential for the insecticidal activity.

Discovery of structurally diverse and bioactive compounds from plant resources in China

This review describes the major discoveries of structurally diverse and/or biologically significant compounds from plant resources in China, mainly from the traditional Chinese medicines (TCMs) since the establishment of our research group in 1999. In the past decade, a large array of biologically significant and novel structures has been identified from plant resources (or TCM) in our laboratory. The structural modification of several biologically important compounds led to more than 400 derivatives, some of which exhibited significantly improved activities and provided opportunities to elucidate the structure-activity relationship of the related compound class. These findings are important for drug discovery and help us understand the biological basis for the traditional applications of these plants in TCM.

Triterpenoids

This review covers the isolation and structure determination of triterpenoids, including squalene derivatives, protostanes, lanostanes, holostanes, cycloartanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, quassinoids, lupanes, oleananes, friedelanes, ursanes, hopanes, serratanes and saponins; 278 references are cited.

Ethnopharmacological use of herbal remedies for the treatment of malaria in the Dangme West District of Ghana

AIM OF STUDY

Malaria is one of the most important diseases in the world. Because of the devastating nature of the disease there is an urgent need to develop new drugs or vaccines for the treatment, prevention and management of the disease. The objective of the present study was to collect and document information on herbal remedies traditionally used for the treatment of malaria in the Dangme West District of Ghana.

METHODS

Data was collected from 67 indigenous households in ten communities in the district using a validated questionnaire.

RESULTS

In total, 30 species of plants belonging to 28 genera in 20 families were reported to be used in the preparation of the herbal remedies. Mature leaves were the most (55%) common plant part used and 73.3% of the herbal remedies involved a single plant. Most of the herbal remedies were prepared by boiling and administered orally. The majority (47%) of the species of plants used were collected from their compounds or home gardens.

CONCLUSIONS

Knowledge about malaria and treatment practices exists in the study area. Herbal remedies were commonly used by people for the treatment of malaria because they were cost-effective. They are also more accessible. Many of the species of plants used have been documented for the treatment of malaria as well as investigated for their phytochemical and antimalarial and/or antiplasmodial activity confirming the results of previous studies as well as rationalization of their traditional use. Five species of plants used in the study area, namely, Bambusa vulgaris Schrad. ex J.C. Wendl. (Poaceae), Deinbollia pinnata Schum. &Thonn. (Sapindaceae), Elaeis guineensis Jacq. (Arecaceae), Greenwayodendron sp. (Annonaceae) and Solanum torvum Sw (Solanaceae), are documented for the first time for their use in the treatment of malaria. "The result of this study provides the basis for further pharmacological studies on the herbal remedies used".

Limonoids and triterpenoids from Khaya senegalensis

Seven new limonoids (1-7), named khayalenoids C-I, three new triterpenoids (8-10), named senegalenes A-C, and eight known limonoids have been isolated from stems of Khaya senegalensis. The structures of these compounds were elucidated on the basis of spectroscopic analyses.