Isolation of a library of aromadendranes from Landolphia dulcis and its characterization using the VolSurf approach

Sesquiterpenoids from Meliaceae Family and Their Biological Activities

Sesquiterpenoids, an important class of natural products possessing three isoprene-derived units, are widely distributed across plants and have a variety of biological activities. All sesquiterpenoids are derived from farnesyl pyrophosphate (FPP), a biosynthesis precursor that can form various carbon skeletons. In order to provide a reference for further research and development of these compounds, this review focused on the increasing number of isolated and volatile sesquiterpenoids found to be produced by plants of the Meliaceae family between 1968 and 2023. The related articles were collected from SciFinder, Google Scholar, and PubMed. According to a literature review, several studies were started for more than 55 years on the plant's stem barks, twigs, leaves, flowers, seeds, and pericarps, where approximately 413 sesquiterpenoid compounds from several groups such as eudesmane, aromadendrane, cadinane, guaiane, bisabolane, furanoeremophilane, humulene, germacrane, and oppositane-type were isolated and identified with some minor products. Additionally, the hypothetical route of sesquiterpenoids biosynthesis from this family was identified, and eudesmane-type was reported to be 27% of the total compounds. The antimicrobial, antidiabetic, antioxidant, antiplasmodial, antiviral, and cytotoxic activities of the isolated compounds and major volatile sesquiterpenoids constituent on essential oil were also evaluated. The result showed the fundamental of using the sesquiterpenoid compounds from the Meliaceae family in traditional medicine and the discovery of new drugs.

The genus Landolphia P.Beauv. (Apocynaceae): A comprehensive review on its ethnobotanical utilizations, pharmacology and nutritional potential

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Landolphia is an important resource for African traditional medicine. Among the 60 different accepted species, nearly every plant part of the genus (bark, fruit, latex, leaf, leaf sap, root, rootbark, twig) from 13 species is utilized by traditional healers around Africa. Accordingly, many pharmacological studies (42) were performed on the most common species (11).

AIM OF THE STUDY

This comprehensive literature review summarizes all publications dealing on one of the 60 plant species from the genus Landolphia. An overview about already performed analysis is given and important aspects and knowledge gaps are highlighted for the direction of future research activities.

MATERIALS AND METHODS

A systematic web search taking into account the major platforms Web of Science, Scopus, PubMed, SciFinder and Google Scholar was performed for the term Landolphia. All relevant datasets, published between 1804 and 2022, were ordered according to their topics in different sections and compared to each other. A network visualization of the keywords via VOS Viewer was additionally performed.

RESULTS

In total, 209 publications were retrieved from the search engines, mainly written in English. Predominant are ethnopharmacological studies, which identified 292 phytochemicals in plant parts of the whole genus. Diverse biological activities were detected in different plant extracts, and five species were determined as of special interest for the treatment of malaria. Further research topics identified are botanical aspects, ethnobotanical utilizations, ecological aspects, the potential as source for human and animal nutrition, the manufacturing of rubber, economic aspects, biomechanical studies and others. L. owariensis is the most studied plant as it is abundant in continental Africa.

CONCLUSIONS

This review serves as a database for upcoming research on the genus Landolphia and directs existing knowledge gaps. A wide range of chemical components are already identified, but their exact content in the respective plant parts and their biological activity remains mainly unknown. Utilization patterns from traditional medicine are only partially analyzed as demonstrated for the applications as aphrodisiac, to treat skin diseases or as antidiabetic. Nutritional analyses likewise focus on several species of Landolphia and lack for the wide range of known edible fruits. The demand for new natural products in terms of medicine, rubber and nutrition is still high and the genus Landolphia seems to be a promising resource covering many aspects at once.

Phytotoxic and Nematicidal Components of Lavandula luisieri

Several preparations were obtained from the aerial parts of predomesticated Lavandula luisieri, including the essential oil and ethanolic, hexane, and ethyl acetate extractives. Additionally, pilot plant vapor pressure extraction was carried out at a pressure range of 0.5-1.0 bar to give a vapor pressure oil and an aqueous residue. A chemical study of the hexane extract led to the isolation of six necrodane derivatives (1, 2, and 4-7), with four of these (1, 2, 5, and 7) being new, as well as camphor, a cadinane sesquiterpene (9), tormentic acid, and ursolic acid. The EtOAc and EtOH extracts contained a mixture of phenolic compounds with rosmarinic acid being the major component. Workup of the aqueous residue resulted in the isolation of the necrodane 3 and (1R*,2S*,4R*)-p-menth-5-ene-1,2,8-triol (8), both new natural compounds. The structures of the new compounds were established based on their spectroscopic data. The phytotoxic and nematicidal activities of these compounds were evaluated.

Secondary metabolites with chemical diversity from the marine-derived fungus Pseudallescheria boydii F19-1 and their cytotoxic activity

Twenty-five compounds with chemical diversity including five new compounds were isolated from the marine-derived fungus Pseudallescheria boydii F19-1. Five compounds displayed significant cytotoxicity against Sf9 cells.

Two New Aromadendrane Sesquiterpenes from the Stem Bark of Alafia multiflora

Two new aromadendrane sesquiterpenoids (1β,4β,5β,6α,7α,11 S)-aromadendr-9-en-13,14-dioic acid (1) and (1β,4β,5β,6α,7α,11 S)-13-oxoaromadendr-9-en-14-oic acid (2) have been isolated from the stem bark of Alafia multiflora along with β-sitosterol and β-sitosterol glucoside. Their structures were established on the basis of spectroscopic analyses, including 1D and 2D NMR experiments (1H-1H COSY, NOESY, HSQC, HMBC). Compound 1 showed a weak growth inhibitory activity against the murine melanoma line B16F10 MTT.

Lochmolins A-G, new sesquiterpenoids from the soft coral Sinularia lochmodes

Seven new sesquiterpenoids, lochmolins A–G (1–7), were isolated from a Taiwanese soft coral Sinularia lochmodes. The structures of these metabolites were elucidated by extensive spectroscopic study. Compounds 1–4 were found to inhibit the accumulation of the LPS-induced pro-inflammatory COX-2 protein in RAW264.7 macrophage cells.

Assessment of the phytochemical and antitrypanosomal properties of some extracts of leaves, stem and root bark of Landolphia sp., P. Beauv

INTRODUCTION/JUSTIFICATION: There is urgent need to source for alternative chemotherapy against trypanosmosis, a disease of major importance in human and economic animals.

MATERIALS AND METHODS

Therefore, petroleum ether, chloroform, methanol and aqueous extracts sequentially obtained from the leaves, stem and root barks of Landolphia uniflora were evaluated for their in vitro and in vivo antitrypanosomal activities against Trypanosoma brucei brucei, as well as their phytochemical constituents.

RESULTS

Steroids and triterpenes, resins, tannins, saponins and flavonosides were detected in almost all the extracts, but alkaloid was absent in methanol extract of the stem and stem, as well as the chloroform extract of the root bark. In vitro, all extracts of the roots displayed significant antitrypanosomal activity, while only the chloroform extracts of the leaves and stem bark showed activity at both test concentrations (4 and 2 mg/ml). However, under in vivo condition, the methanol extracts showed the greatest activity, eliminating parasitaemia within the 10 days treatment period and prolonging survival period at 200 and 300 mg/kg body weight intramuscular doses.

CONCLUSION

These results suggest that Landolphia uniflora could be useful in the management of trypanosomiasis.

The function of terpene natural products in the natural world

As the largest class of natural products, terpenes have a variety of roles in mediating antagonistic and beneficial interactions among organisms. They defend many species of plants, animals and microorganisms against predators, pathogens and competitors, and they are involved in conveying messages to conspecifics and mutualists regarding the presence of food, mates and enemies. Despite the diversity of terpenes known, it is striking how phylogenetically distant organisms have come to use similar structures for common purposes. New natural roles undoubtedly remain to be discovered for this large class of compounds, given that such a small percentage of terpenes has been investigated so far.