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A phytochemical investigation on the 90% ethanol extract of the leaves of Croton lachnocarpus Benth. led to three new ent -abietane diterpenoids, 7 β ,15-dihydroxy- ent -abieta-8,11,13-trien-3-one ( 1 ), 2 β ,15-dihydroxy- ent -abieta-8,11,13-triene ( 2 ), and 7 β ,13 α ,15-trihydroxy- ent -abieta-8(14)-en-3-one ( 3 ). Structural elucidation of all the compounds were performed by spectral methods such as 1 D and 2 D ( 1 H - 1 H COSY, HMQC, NOESY and HMBC) NMR spectroscopy, in addition to electronic circular dichroism (ECD) spectra. The isolated compounds were tested in vitro for cytotoxic activity against 6 tumor cell lines. As a result, compound 3 exhibited some cytotoxicities against all the tested tumor cell lines with IC 50 value less than 30 μM.

Three new ent -abietane diterpenoids, 6 β -hydroxy- ent -abieta-7,13-dien-3-one ( 1 ), 2 β ,13 α ,15-trihydroxy- ent -abieta-8(14)-en-3-one ( 2 ), and 2 β ,9 α ,13 β ,15-tetrahydroxy- ent -abieta-7-en-3-one ( 3 ), were isolated from 90% ethanol extract of the leaves of Croton cascarilloide . Their structures were determined by spectral methods such as 1D and 2D ( 1 H - 1 H COSY, HMQC, NOESY, and HMBC) NMR spectroscopy, in addition to electronic circular dichroism (ECD) spectra. The isolated diterpenoids were tested in vitro for antimicrobial activity against 6 pathogenic microorganisms. As a result, compounds 1-3 exhibited antimicrobial activity against the tested Gram positive bacteria with minimum inhibitory concentration values less than 50 μg/ml.

One new clerodane-type diterpenoid, together with one known, was isolated from the leaves and twigs of C. krabas . The structures of these compounds were elucidated as krabasinolide A ( 1 ) and taraxerol ( 2 ) by spectroscopic methods (UV, IR, HRESIMS, 1 D, and 2 D NMR), and the relative stereochemistry was confirmed by X-ray diffraction analysis with graphite monochromated Mo-Kα (λ = 0.71073 Å) radiation at 296(2) K. Extracts and compounds 1 - 2 were evaluated for in vitro antiviral activity.

Purpose: This study was aimed at investigating the protective effect of antioxidant-rich fraction of Croton zambsicus (C-ZAMB) leaves on ocular-gastrointestinal dysfunction in rats exposed to environmental mixed-metal (EOMABRSL)., Materials and Methods: The rats were divided into five ( n  = 10) groups. Group I designates the control which received 0.5 mL of distilled water. Group II and III received 0.5 mL of EOMABRSL for 98 days (non-withdrawal) and 70 days (withdrawal for 28 days), respectively. Group IV received 0.5 mL EOMABRSL for 70 days and 400 mg/kg C-ZAMB fraction for 28 days. Group V received 400 mg/kg C-ZAMB only for 28 days via oral route., Results: Exposure of the animals to EOMARBSL for 98 days and 70 days significantly up-regulated the activities of ocular-gastrointestinal aldolase-reductase, α-amylase, α-glucosidase and eco-5 1 -nucleotidase with corresponding depletion of lactate dehydrogenase activity. Furthermore, exposure to EOMABRSL significantly altered the antioxidant proteins with up-production of MDA content. Apparently, management with 400 mg/kg C-ZAMB fraction significantly inhibited the key markers linked with ocular-gastrointestinal disorders., Conclusion: Hence, this study underscores the biochemical mechanisms for managing ocular-gastrointestinal lesions by 400 mg/kg C-ZAMB fraction on exposure to mixture of environmental metals.

Phytochemical investigation of Croton crassifolius roots afforded five sesquiterpenes ( 1-5 ), including two new sesquiterpenes 6 S -hydroxy-cyperenoic acid ( 1 ) and crassifterpenoid A ( 5 ), together with three known compounds ( 2-4 ). The structures of the new compounds were determined by comprehensive spectroscopic methods, and their absolute configurations were determined by quantum chemical ECD calculation. Crassifterpenoid A ( 5 ) is the first germacrane-type sesquiterpene isolated from C. crassifolius , which enriched the diversity of chemical constituents in Croton crassifolius . In addition, the cytotoxicities of all compounds against human liver cancer lines HepG2 and Hep3B were determined, but none showed significant activity.

Chemical study on the ethanolic extract generated from the aerial parts of Croton kongensis led to the isolation of three new 8,9-seco-ent-kaurane diterpenoids, kongeniods A‒C (1‒3), together with seven known analogs (4-10). The structures of these compounds were assigned by spectroscopic data analysis. The vitro cytotoxic tests showed that compounds 1-3 exhibited strong activities against HL-60 cell lines with IC 50 values of 0.47, 0.58, and 1.27 μM, respectively.

Six new ent-labdane-type diterpeniods (1‒6), along with one known compound, were identified from the twigs and leaves of Croton laevigatus. Their structures were elucidated on the basis of extensive spectroscopic interpretation. Compounds 2 and 7 showed inhibitory activity against protein tyrosine phosphatase 1B (PTP1B) with IC 50 values of 4.11 and 8.33 μg/ml, respectively.

Phytochemical investigation of the ethanol extract from the twigs and leaves of Croton tiglium led to the isolation of two new phorbol esters (1-2) and seven known ones (3-9). Their structures were elucidated by the analyses of extensive spectroscopic data (IR, MS, and 1D and 2D NMR) and comparing with related compounds. Meanwhile, compounds 1-9 were determined for their cytotoxic activities on human lung cancer cell line A549. Among them, 1-2 were inactive against the cell line A549 (IC 50  > 100 μM), but compounds 3 and 7 showed weak activities.

Two new clerodane-type diterpenoids were isolated from the roots of Croton crassifolius Geisel. The structures of these compounds were elucidated as 9-[2-(2(5H)-furanone-4-yl)ethyl]-4,8,9-trimethyl-1,2,3,4,5,6,7,8-octahydronaphthalene-4-carboxylic acid (1) and methyl 9-[2-(2(5H)-furanone-4-yl)ethyl]-4,8,9-trimethyl-1,2,3,4,5,6,7,8-octahydronaphthalene-4-carboxylic ester (2) by spectroscopic methods.

Plaunotol is an acyclic diterpene alcohol extracted from a medicinal plant called plau-noi, Croton stellatopilosus Ohba, and has been widely used for the treatment of gastric ulcers in Japan. The aim of this study was to examine the effects of plaunotol on human gingival fibroblasts (HGFs) and human oral keratinocytes (HOKs). To assess the cytotoxic effect, HGFs and HOKs were treated with plaunotol. Subsequently, the morphology of cells was recorded and cells were subjected to MTT assay. To investigate cell proliferation effect, cells were treated with plaunotol and counted with a haemocytometer. To determine wound healing effect, the number of cells repopulated into the wounded areas in monolayer culture and in fibroblast-populated collagen lattice (FPCL) was measured. The results showed that 10 and 1 μg/ml (33 and 3.3 μmol/l) plaunotol induced toxicity in HGFs and HOKs, respectively. However, 0.1 μg/ml (0.33 μmol/l) plaunotol promoted HGF proliferation and wound healing in monolayer and FPCL models. In contrast, 0.1 μg/ml plaunotol could not induce HOK proliferation nor in vitro wound healing using monolayer culture, but it induced wound healing in a modified FPCL model. Our data suggested that plaunotol could promote oral cell proliferation and wound healing in vitro and may have an implication on oral wound healing.

Two new amides crotamides A and B, have been isolated from the n-hexane soluble fraction of Croton sparsiflorus in addition to salisomide and N-(4-hydroxyphenethyl)-octacosanamide reported for the first time from this species. Their structures were assigned from spectral data including 1D and 2D NMR spectroscopic data.

A novel analgesic pyrazine derivative, named crotonine, was isolated from the leaves of Croton tiglium L. The structure was elucidated as 2-(furan-2-yl)-5-(2,3,4-trihydroxy-butyl)-1,4-diazine by spectroscopic analysis. Crotonine inhibited remarkably the acetic acid-induced writhing in mice.