Moluccensins R-Y, limonoids from the seeds of a mangrove, Xylocarpus moluccensis

Terpenoid phytocompounds from mangrove plant Xylocarpus moluccensis as possible inhibitors against SARS-CoV-2: In silico strategy

COVID-19 shook the world during the pandemic, where the climax it reached was vaccine manufacturing at an unfathomable pace. Alternative promising solutions to prevent infection from SARS-CoV-2 and its variants will remain crucial in the years to come. Due to its key role in viral replication, the major protease (Mpro) enzyme of SARS-CoV-2 can be an attractive therapeutic target. In the present work, natural terpenoids from mangrove medicinal plant Xylocarpus moluccensis (Lam.) M. Roem. were screened using computational methods for inhibition of Mpro protein. Out of sixty-seven terpenoids, Angolensic acid methyl ester, Moluccensin V, Thaixylomolin F, Godavarin J, and Xylomexicanolide A were shortlisted based on their docking scores and interaction affinities (- 13.502 to - 15.52 kcal/mol). The efficacy was validated by the 100 ns molecular dynamics study. Lead terpenoids were within the acceptable range of RMSD and RMSF with a mean value of 2.5 Å and 1.5 Å, respectively indicating that they bound tightly within Mpro and there was minimal fluctuation and stability of Mpro upon binding of these terpenoids. The utmost favorable binding strengths as calculated by MM-GBSA, were of Angolensic acid methyl ester and Moluccensin V with binding free energies (ΔGbind) of - 39.084, and - 43.160 kcal/mol, respectively. The terpenoids showed no violations in terms of Drug Likeliness and ADMET predictions. Overall, the findings indicate that Angolensic acid methyl ester and Moluccensin V are effective terpenoids having strong binding interaction with Mpro protein, which must be tested in vitro as an effective anti-SARS-CoV-2 drug.

Research progress of meliaceous limonoids from 2011 to 2021

Covering: July 2010 to December 2021Limonoids, a kind of natural tetranortriterpenoids with diverse skeletons and valuable insecticidal and medicinal bioactivities, are the characteristic metabolites of most plants of the Meliaceae family. The chemistry and bioactivities of meliaceous limonoids are a continuing hot area of natural products research; to date, about 2700 meliaceous limonoids have been identified. In particular, more than 1600, including thirty kinds of novel rearranged skeletons, have been isolated and identified in the past decade due to their wide distribution and abundant content in Meliaceae plants and active biosynthetic pathways. In addition to the discovery of new structures, many positive medicinal bioactivities of meliaceous limonoids have been investigated, and extensive achievements regarding the chemical and biological synthesis have been made. This review summarizes the recent research progress in the discovery of new structures, medicinal and agricultural bioactivities, and chem/biosynthesis of limonoids from the plants of the Meliaceae family during the past decade, with an emphasis on the discovery of limonoids with novel skeletons, the medicinal bioactivities and mechanisms, and chemical synthesis. The structures, origins, and bioactivities of other new limonoids were provided as ESI. Studies published from July 2010 to December 2021 are reviewed, and 482 references are cited.

Exploring the Mangrove Fruit: From the Phytochemicals to Functional Food Development and the Current Progress in the Middle East

Nowadays, the logarithmic production of existing well-known food materials is unable to keep up with the demand caused by the exponential growth of the human population in terms of the equality of access to food materials. Famous local food materials with treasury properties such as mangrove fruits are an excellent source to be listed as emerging food candidates with ethnomedicinal properties. Thus, this study reviews the nutrition content of several edible mangrove fruits and the innovation to improve the fruit into a highly economic food product. Within the mangrove fruit, the levels of primary metabolites such as carbohydrates, protein, and fat are acceptable for daily intake. The mangrove fruits, seeds, and endophytic fungi are rich in phenolic compounds, limonoids, and their derivatives as the compounds present a multitude of bioactivities such as antimicrobial, anticancer, and antioxidant. In the intermediary process, the flour of mangrove fruit stands as a supplementation for the existing flour with antidiabetic or antioxidant properties. The mangrove fruit is successfully transformed into many processed food products. However, limited fruits from species such as Bruguiera gymnorrhiza, Rhizophora mucronata, Sonneratia caseolaris, and Avicennia marina are commonly upgraded into traditional food, though many more species demonstrate ethnomedicinal properties. In the Middle East, A. marina is the dominant species, and the study of the phytochemicals and fruit development is limited. Therefore, studies on the development of mangrove fruits to functional for other mangrove species are demanding. The locally accepted mangrove fruit is coveted as an alternate food material to support the sustainable development goal of eliminating world hunger in sustainable ways.

Limonoids from Swietenia macrophylla and their antitumor activities in A375 human malignant melanoma cells

Swietelinins A - C (1-3) and swieteliacates F - R (4-16), sixteen new limonoids and 18 known limonoids (17-34) were isolated from Swietenia macrophylla. The absolute configurations of these compounds were defined by using a combination of electronic circular dichroism data analysis and single-crystal X-ray diffraction data. Swieteliacate J (10) is the first limonoid possessing an unusual 8β, 9β-epoxy ring system. All of the compounds were tested for cytotoxicity against four human tumor cell lines (SMMC-7721, SW620, A549, and A375). Compounds 10, 11, and 19 exhibited selectively moderate cytotoxicity against four tumor cell lines, especially 19 exhibited significant cytotoxic effects against A375 with IC₅₀ an value of 9.8 μM and was more active than the positive control, dacarbazine with an IC₅₀ value of 22.4 μM. Compound 19 effectively induced apoptosis of A375, which was associated with G2/M-phase cell cycle arrest. Flow cytometric analysis showed that the treatment by 19 significantly induced A375 cell apoptosis in a dose-dependent manner.

Triterpenes and limonoids of Cedrela: Distribution, biosynthesis, and 1 H and 13 C NMR data

Cedrela genus, a member of the Meliaceae family, presents both chemical characteristics associated with and those that distinguish it from the rest of its members. The presence of triterpenes and limonoids is the characteristic of the Meliaceae family, but the class and type of these chemical constituents are distinctive for each genus. Cedrela includes cycloartane, ursane, oleanane, tirucallane, butyrospermane, and apotirucallane triterpenes, and its limonoids belongs to six class and nine types, known as class Ia-type havanensines, class Ib-type delevoyin, class II-type gedunin, class IIIb-type andirobin, class IIIg-type mexicanolide, class IVa-type evoludone, class Va-type obacunol, class V-type limonin, and class VIII. Each of these structural arrangements includes specific traits, defined by their biosynthetic origin, which can be established by means of structural elucidation techniques, particularly ¹ H and ¹³ C NMR, which assisted by 2D NMR techniques, allowing to deduce their structures unequivocally. The constant presence of these skeletal arrangements in Cedrela ensures that they are its chemophenetic markers and their recurrence is an important criterion for their identity. This review is a compilation of the occurrence of triterpenes and limonoids in Cedrela genus, detailing their biosynthetic association and collecting and organizing their NMR data, with the purpose of facilitating its location, analysis, and use in the phytochemical study of species from this genus.

Chemical profile and therapeutic potentials of Xylocarpus moluccensis (Lam.) M. Roem.: A literature-based review

ETHNOPHARMACOLOGICAL RELEVANCE

Historically, mangrove plants are among the potential sources of foods and remedies for humans living in the forests and nearby communities. Xylocarpus moluccensis (Lam.) M. Roem., an important mangrove medicinal plant, has been traditionally used for many purposes such as treatment of fever, dysentery, diarrhea, swelling, and abdominal disorders. The aim of the present work was to summarize the chemical reports and biological activities of the mangrove medicinal plant X. moluccensis based on information collected from different databases.

MATERIALS AND METHODS

An up-to-date search (till Aug 2019) was carried out in databases such as PubMed, Science Direct, Google Scholar, and various patient offices (e.g., WIPO, CIPO, USPTO) using the keywords: 'Xylocarpus moluccensis', and/or paired with 'ethnobotanical use', and 'phytochemical'. In vitro, ex vivo, or in vivo studies were included.

RESULTS

Findings suggest that X. moluccensis contains various important minerals and phytochemicals, where flavonoids, terpenes and terpenoids are the most prominent isolated phyto-constituents of X. moluccensis. Extracts/fractions or isolated compounds from this plant possess diverse biological activities, including anti-inflammatory, anti-microbial, antineoplastic, anti-diarrheal, insecticidal, anti-feedant, neuropharmacological (e.g., central nervous system depressant), anti-atherosclerotic, and lipid-lowering activity. Only one report suggests that the methanol and aqueous extracts of this plant did not exert cytotoxic effects on normal mouse fibroblast cells. However, no clinical studies were reported.

CONCLUSIONS

Taken all together, X. moluccensis may be one of the best sources of pharmacologically active lead compounds. More research, however, is necessary to establish the safety and efficacy, and its toxicogenetic effects in animal models.

TDDFT-ECD and DFT-NMR studies of thaigranatins A–E and granatumin L isolated from Xylocarpus granatum

TDDFT-ECD calculations were utilized to explain the mirror image or different ECD spectra of thaigranatins A–E and granatumin L.

Six New Phragmalin Limonoids from the Stems of Chukrasia tabularis A. Juss

Six new phragmalin limonoids, named moluccensin Z1 (1), moluccensin Z2 (2), carapanolide Y (3), tabulalin N (4), chukvelutilide A1 (5), and velutinasin J (6), as well as two known compounds, chukvelutilide A (7) and velutinasin D (8) were isolated from the stems of Chukrasia tabularis A. Juss. The structures of the new compounds 1–6 were confirmed by spectroscopic methods, including IR and HRESIMS, as well as 1D and 2D NMR, and by comparisons with the data of known analogues. All compounds were tested for α-glucosidase and acetylcholinesterase inhibitory activities. However, none of the compounds was active against α-glucosidase and acetylcholinesterase in vitro.

Twenty-Nine New Limonoids with Skeletal Diversity from the Mangrove Plant, Xylocarpus moluccensis

Twenty-nine new limonoids—named xylomolins A₁–A₇, B₁–B₂, C₁–C₂, D–F, G₁–G₅, H–I, J₁–J₂, K₁–K₂, L₁–L₂, and M–N, were isolated from the seeds of the mangrove plant, Xylocarpus moluccensis. Compounds 1–13 are mexicanolides with one double bond or two conjugated double bonds, while 14 belongs to a small group of mexicanolides with an oxygen bridge between C1 and C8. Compounds 15–19 are khayanolides containing a Δ^8,14 double bond, whereas 20 and 21 are rare khayanolides containing a Δ^14,15 double bond and Δ^8,9, Δ^14,15 conjugated double bonds, respectively. Compounds 22 and 23 are unusual limonoids possessing a (Z)-bicyclo[5.2.1]dec-3-en-8-one motif, while 24 and 25 are 30-ketophragmalins with Δ^8,9, Δ^14,15 conjugated double bonds. Compounds 26 and 27 are phragmalin 8,9,30-ortho esters, whereas 28 and 29 are azadirone and andirobin derivatives, respectively. The structures of these compounds, including absolute configurations of 15–19, 21–23, and 26, were established by HRESIMS, extensive 1D and 2D NMR investigations, and the comparison of experimental electronic circular dichroism (ECD) spectra. The absolute configuration of 1 was unequivocally established by single-crystal X-ray diffraction analysis, obtained with Cu Kα radiation. The diverse cyclization patterns of 1–29 reveal the strong flexibility of skeletal plasticity in the limonoid biosynthesis of X. moluccensis. Compound 23 exhibited weak antitumor activity against human triple-negative breast MD-MBA-231 cancer cells with an IC₅₀ value of 37.7 μM. Anti-HIV activities of 1, 3, 8, 10, 11, 14, 20, 23–25, and 27 were tested in vitro. However, no compounds showed potent inhibitory activity.

Scaffold diversity-oriented synthesis of limonoid dimers: discovery of an axially chiral agent within vivoanti-breast cancer activity

Eight new limonoid dimers of four skeletons were synthesized. The axially chiral dimer5bexhibitedin vivoanti-breast cancer activity.

Antiviral Limonoids Including Khayanolides from the Trang Mangrove Plant Xylocarpus moluccensis

Eight new khayanolides, named thaixylomolins G-N (1-8), two new phragmalins (9 and 10), and two new mexicanolides (11 and 12) were obtained from the seeds of the Trang mangrove plant Xylocarpus moluccensis. The absolute configurations of these limonoids, except for the stereocenter at C-6 of 11 and 12, were assigned by experimental and TDDFT calculated electronic circular dichroism spectra. The khayanolides may be classified into two subclasses, one of which has a C-2 carbonyl and a 3β-acetoxy group, whereas the other possesses a 2β-acetoxy and a C-3 carbonyl function. Khayanolides, rearranged phragmalin-type limonoids, are reported for the first time from plants of the mangrove genus Xylocarpus. The structure of moluccensin J, a known 30-ketophragmalin containing a Δ(8(14)) double bond, was revised to be a khayanolide, named thaixylomolin K. The antiviral activities of the isolates against pandemic influenza A virus (subtype H1N1) were tested by the assay of cytopathic effect inhibition. Three khayanolides, viz., thaixylomolins I, K, and M, exhibited moderate anti-H1N1 activities. The most potent one, thaixylomolin I (IC50 = 77.1 ± 8.7 μM), showed stronger inhibitory activity than that of the positive control, ribavirin (IC50 = 185.9 ± 16.8 μM).

Triterpenoids

This review covers the isolation and structure determination of triterpenoids reported during 2012 including squalene derivatives, lanostanes, holostanes, cycloartanes, cucurbitanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, quassinoids, lupanes, oleananes, friedelanes, ursanes, hopanes, serratanes, isomalabaricanes and saponins; 348 references are cited.

Limonoids from Aphanamixis polystachya and their antifeedant activity

Eight new aphanamixoid-type aphanamixoids (C-J, 1-8) and six new prieurianin-type limonoids, aphanamixoids K-P (9-14), along with 10 known terpenoids were isolated from Aphanamixis polystachya, and their structures were established by spectroscopic data analysis. Among the new limonoids, 13 compounds exhibited antifeedant activity against the generalist Helicoverpa armigera, a plant-feeding insect, at various concentration levels. In particular, compounds 1, 4, and 5 showed potent activities with EC50 values of 0.017, 0.008, and 0.012 μmol/cm(2), respectively. On the basis of a preliminary structure-activity relationship analysis, some potential active sites in the aphanamixoid-type limonoid molecules are proposed.

Marine natural products

This review covers the literature published in 2012 for marine natural products, with 1035 citations (673 for the period January to December 2012) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1241 for 2012), together with the relevant biological activities, source organisms and country of origin. Biosynthetic studies, first syntheses, and syntheses that lead to the revision of structures or stereochemistries, have been included.

Can scientific evidence support using Bangladeshi traditional medicinal plants in the treatment of diarrhoea? A review on seven plants

Diarrhoea is a common disease which causes pain and may be deadly, especially in developing countries. In Bangladesh, diarrhoeal diseases affect thousands of people every year, and children are especially vulnerable. Bacterial toxins or viral infections are the most common cause of the disease. The diarrhoea outbreaks are often associated with flood affected areas with contaminated drinking water and an increased risk of spreading the water-borne disease. Not surprisingly, plants found in the near surroundings have been taken into use by the local community as medicine to treat diarrhoeal symptoms. These plants are cheaper and more easily available than conventional medicine. Our question is: What is the level of documentation supporting the use of these plants against diarrhoea and is their consumption safe? Do any of these plants have potential for further exploration? In this review, we have choosen seven plant species that are used in the treatment of diarrhoea; Diospyros peregrina, Heritiera littoralis, Ixora coccinea, Pongamia pinnata, Rhizophora mucronata, Xylocarpus granatum, and Xylocarpus moluccensis. Appearance and geographical distribution, traditional uses, chemical composition, and biological studies related to antidiarrhoeal activity will be presented. This review reveals that there is limited scientific evidence supporting the traditional use of these plants. Most promising are the barks from D. peregrina, X. granatum and X. moluccensis which contain tannins and have shown promising results in antidiarrhoeal mice models. The leaves of P. pinnata also show potential. We suggest these plants should be exploited further as possible traditional herbal remedies against diarrhoea including studies on efficacy, optimal dosage and safety.

New azalomycin F analogs from mangrove Streptomyces sp. 211726 with activity against microbes and cancer cells

Seven new azalomycin F analogs (1-7) were isolated from the broth of mangrove Streptomyces sp. 211726, and respectively identified as 25-malonyl demalonylazalomycin F5a monoester (1), 23-valine demalonylazalomycin F5a ester (2), 23-(6-methyl)heptanoic acid demalonylazalomycins F3a ester (3), F4a ester (4) and F5a ester (5), 23-(9-methyl)decanoic acid demalonylazalomycin F4a ester (6) and 23-(10-methyl)undecanoic acid demalony lazalomycin F4a ester (7). Their structures were established by their spectroscopic data and by comparing with those of azalomycins F3a, F4a and F5a. Biological assays exhibited that 1-7 showed broad-spectrum antimicrobial and anti HCT-116 activities.