Novel γ-lactone derivatives from Trigonostemon heterophyllus with their potential antiproliferative activities

Nature's Green Potential: Anticancer Properties of Plants of the Euphorbiaceae Family

The number of cancer cases will reach 24 million in 2040, according to the International Agency for Research on Cancer. Current treatments for cancer are not effective and selective for most patients; for this reason, new anticancer drugs need to be developed and researched enough. There are potentially useful drugs for cancer isolated from plants that are being used in the clinic. Available information about phytochemistry, traditional uses, in vitro and in vivo experiments with plants, and pure compounds isolated from the Euphorbiaceae family indicates that this family of plants has the potential to develop anticancer drugs. This review examines selected species from the Euphorbiaceae family and their bioactive compounds that could have potential against different types of cancer cells. It reviews the activity of crude extracts, isolated compounds, and nanoparticles and the potential underlying mechanisms of action.

Xanthones with Potential Anti-Inflammatory and Anti-HIV Effects from the Stems and Leaves of Cratoxylum cochinchinense

Four new xanthones, cratocochinones A-D (1-4), together with eight known analogues (5-12), were isolated from the stems and leaves of Cratoxylum cochinchinense. The chemical structures of cratocochinones A-D (1-4) were elucidated by comprehensive spectroscopic analyses and the known compounds were identified by comparisons with the spectral data reported in the literature. All isolated compounds 1-12 were evaluated for their anti-inflammatory activities and anti-HIV-1 activities. Compounds 1-12 showed remarkable inhibitory activities on nitric oxide (NO) production induced by lipopolysaccharide in mouse macrophage RAW 264.7 cells in vitro, with IC50 values in the range of 0.86 ± 0.05 to 18.36 ± 0.21 µM. Meanwhile, compounds 1-12 exhibited significant anti-HIV-1 activities with EC50 which ranged from 0.22 to 11.23 µM. These findings indicate that the discoveries of these xanthones, isolated from the stems and leaves of C. cochinchinense, showing significant anti-inflammatory and anti-HIV-1 effects could be of great importance to the research and development of new natural anti-inflammatory and anti-HIV agents.

Syzysamalactone, an Unusual 11-Carbon δ-Lactone Derivative from the Fresh Ripe Fruits of Syzygium samarangense (Wax Apple)

To study the chemical constituents from the ripe fresh fruits of Syzygium samarangense (wax apple) and their potential health effects, a phytochemical investigation was undertaken. A new δ-lactone derivative, syzysamalactone (1), along with a known biogenetically related δ-lactone derivative, 6-pentyl-α-pyrone (2), were isolated from the fresh ripe fruits of S. samarangense. Syzysamalactone (1) is an unusual 11-carbon δ-lactone derivative, and its chemical structure and absolute configuration were elucidated by spectroscopic data analysis. A plausible biogenetic pathway for 1 was also proposed. Furthermore, the potential neuroprotective effects of compounds 1 and 2 were assessed. As a result, compounds 1 and 2 displayed notable neuroprotective effects with EC₅₀ values of 0.29 ± 0.03 and 1.28 ± 0.06 μM, respectively, using the SH-SY5Y human neuroblastoma cell line. This is the first report of δ-lactone derivatives showing significant neuroprotective activities.

Artapilosines A and B, Unusual Phenanthrene Derivatives Related to Aporphine Alkaloids from Artabotrys pilosus

Two unusual phenanthrene derivatives related to aporphine alkaloids, artapilosines A (1) and B (2), as well as two biogenetically related known aporphine alkaloids, (-)-anonaine (3) and (-)-N-acetylanonaine (4), were separated and purified from Artabotrys pilosus. Artapilosine A (1) is the first compound representative of a new class of phenanthrene derivatives having an unprecedented carbon skeleton, in which the six-membered nitrogen-containing heterocyclic structure in a typical aporphine alkaloid was substituted with a unique five-membered carbocyclic ring. This is the first report of the formation of a carbon-carbon bond between C-5 and C-6a in 1 with the loss of the nitrogen atom N-6 in the classic aporphine alkaloid. Artapilosine B (2) is a novel phenanthrene derivative having a hydroxyethyl as a substituent on the phenanthrene ring. Their chemical structures as well as absolute configurations were determined based on analysis of spectroscopic data. Additionally, the potential anti-HIV activities of all isolates 1-4 were appraised. Artapilosines A (1) and B (2) showed notable anti-HIV reverse transcriptase affects, with EC₅₀ values of 20.93 and 125.29 nM, respectively. These results suggested that the discovery of these novel phenanthrene derivatives from A. pilosus with remarkable anti-HIV effects could be essentially important for the researching and developing of new anti-HIV agents.

Clausanisumine, a Prenylated Bicarbazole Alkaloid from the Fruits of Clausena anisum-olens and Its Potential Anti-HIV Activity

A unique prenylated bicarbazole alkaloid, clausanisumine (1), and two biogenetically related known monomer carbazole alkaloids, mukonal (2) and 3-methylcarbazole (3), were isolated from the fruits of Clausena anisum-olens. Clausanisumine (1) was an uncommon prenylated bicarbazole alkaloid, possessing an unprecedented carbon skeleton, which was composed of a simple carbazole alkaloid and a prenylated carbazole alkaloid. The chemical structure of 1 was established by a combination of comprehensive spectral methods. A plausible biosynthetic pathway of 1 was also proposed. Additionally, the potential anti-HIV activities of all isolates 1-3 in vitro were evaluated. Compound 1 exhibited remarkable anti-HIV-1 reverse transcriptase effects showing an EC₅₀ value of 18.58 nM. The discovery of the prenylated bicarbazole alkaloid from C. anisum-olens with notable anti-HIV activity would be meaningful to discovering and developing new anti-HIV drugs.

Anthraquinones with potential antiproliferative activities from the fruits of Morinda citrifolia

The phytochemical investigation on the fruits of Morinda citrifolia led to the isolation and characterization of a new anthraquinone, moricitrifone (1), along with seven known anthraquinones (2-8). The chemical structure of 1 was elucidated by extensive spectral analyses. The known compounds (2-8) were identified by comparing their spectral data with those reported in the literature. The antiproliferative activities of all isolated anthraquinones (1-8) against five human cancer cell lines: HL-60, SMMC-7721, A-549, MCF-7 and SW480 were evaluated in vitro. Compounds 1-8 exhibited remarkable antiproliferative activities with IC₅₀ values ranging from 0.26 ± 0.05 to 16.58 ± 0.18 μM, which were comparable to those of doxorubicin.

Trigonostemon species in south China: Insights on its chemical constituents towards pharmacological applications

ETHNOPHARMACOLOGY RELEVANCE

The Euphorbiaceae family, which contains about 300 genera and more than 5000 species, is widely distributed in different regions. Trigonostemon genus comprises a wide group of tropical and temperate plants belonging to the Euphorbiaceae family. This genus includes at least 50 species throughout tropical Asia, extending from India and Sri Lanka to New Guinea. They have been employed by local populations for the treatment of asthma, poisonous snake bites, and food poisoning.

AIM OF THE REVIEW

The main aim of the review is to critically analyze the reported traditional uses, bioactive chemical constituents and pharmacological activities of Trigonostemon species.

MATERIALS AND METHODS

Scientific databases, including Google Scholar, PubMed, CNKI, SpringerLink, Web of Science, Wiley Online Library and SciFinder, were searched using keywords such as "Trigonostemon", "South China", "chemical constituents", or "traditional use". Thus, available articles from 2000 to 2020 were collected and analyzed.

RESULTS AND DISCUSSION

This paper provides systematic data that Trigonostemon species possess a diverse phytochemical composition, (including diterpenes, alkaloids, coumarins, lignins, sesquiterpenes, triterpenoids, flavonoids, and polyphenols) found in different plant organs. Research on Trigonostemon plants has revealed critical therapeutic properties, such as antiviral, anti-tumor, antimicrobial, anti-inflammatory, and insecticidal activities.

CONCLUSIONS

It is envisaged that the current review will add value to more scientific research on Trigonostemon species and enhance/promote the increased interest in the sustainable use of Trigonostemon species as well as lead to the validation of unverified ethnobotanical claims. Future studies on Trigonostemon species would focus on establishing the links between the traditional uses, active compounds and reported pharmacological activities.

Carbazole alkaloids from the fruits of Clausena anisum-olens with potential PTP1B and α-glucosidase inhibitory activities

The phytochemical investigation on the fruits of Clausena anisum-olens led to the isolation of 18 carbazole alkaloids (1-18), containing three new ones, clausenanisines A-C (1-3), and three new naturally occurring carbazole alkaloids, clausenanisines D-F (4-6), as well as 12 known analogues (7-18). The chemical structures of clausenanisines A-F (1-6) were elucidated by extensive spectroscopic methods. Notably, clausenanisine A (1) was a novel carbazole alkaloid with a unique five-membered cyclic ether, while clausenanisine E (5) is an unusual carbazole alkaloid owning an unprecedented naturally occurring carbon skeleton possessing 14 carbon atoms. The known carbazole alkaloids (7-18) were identified by the comparison of their spectral data with those data reported in the literature. All known carbazole alkaloids 7-18 were isolated from C. anisum-olens for the first time. Moreover, all isolated compounds 1-18 were assessed for their protein tyrosine phosphatase 1B (PTP1B) and α-glucosidase inhibitory activities in vitro. Compounds 1-18 exhibited remarkable PTP1B inhibitory activities with IC₅₀ values in the range of 0.58 ± 0.05 to 38.48 ± 0.32 μM, meanwhile, compounds 1-18 displayed significant α-glucosidase inhibitory activities with IC₅₀ values ranging from 3.28 ± 0.16 to 192.23 ± 0.78 μM. These research results imply that the separation and identification of these carbazole alkaloids showing notable PTP1B and α-glucosidase inhibitory activities from the fruits of C. anisum-olens can be very significant for discovering and developing new PTP1B inhibitors and α-glucosidase inhibitors for the treatment of diabetes mellitus.

Limonoids from the Fresh Young Leaves and Buds of Toona sinensis and Their Potential Neuroprotective Effects

Toona sinensis, popularly known as Chinese toon or Chinese mahogany, is a perennial deciduous arbor belonging to the genus Toona in the Meliaceae family, which is widely distributed and cultivated in eastern and southeastern Asia. Its fresh young leaves and buds have been consumed as a very popular nutritious vegetable in China and confirmed to display a wide variety of biological activities. To investigate the chemical constituents and their potential health benefits from the fresh young leaves and buds of T. sinensis, a phytochemical study on its fresh young leaves and buds was therefore undertaken. In our current investigation, 16 limonoids (1-16), including four new limonoids, toonasinenoids A-D (1-4), and a new naturally occurring limonoid, toonasinenoid E (5), were isolated and characterized from the fresh young leaves and buds of T. sinensis. The chemical structures and absolute configurations of limonoids 1-5 were elucidated by comprehensive spectroscopic data analyses. All known limonoids (6-16) were identified via comparing their experimental spectral data containing mass spectrometry data, ¹H and ¹³C nuclear magnetic resonance data, and optical rotation values to the data reported in the literature. All known limonoids (6-16) were isolated from T. sinensis for the first time. Furthermore, the neuroprotective effects of all isolated limonoids 1-16 against 6-hydroxydopamine-induced cell death in human neuroblastoma SH-SY5Y cells were assessed in vitro. Limonoids 1-16 exhibited notable neuroprotective activities, with EC₅₀ values in the range from 0.27 ± 0.03 to 17.28 ± 0.16 μM. These results suggest that regular consumption of the fresh young leaves and buds of T. sinensis might prevent the occurrence and development of Parkinson's disease (PD). Moreover, the isolation and characterization of these limonoids that exhibit notable neuroprotective activities from the fresh young leaves and buds of T. sinensis could be very significant for researching and developing new neuroprotective drugs used for the prevention and treatment of PD.

Bioactive prenylated coumarins as potential anti-inflammatory and anti-HIV agents from Clausena lenis

The phytochemical study on the stems of Clausena lenis resulted in the isolation of three new prenylated coumarins, clauselenins A-C (1-3), together with nine known prenylated coumarins (4-12). The chemical structures of new prenylated coumarins (1-3) were elucidated by means of comprehensive spectral analyses and the known compounds (4-12) were determined by means of comparing their experimental spectral data with those described data in the literatures. All isolated prenylated coumarins were assessed for their anti-inflammatory effects together with anti-HIV activities in vitro. Prenylated coumarins 1-12 displayed remarkable inhibitory effects against nitric oxide (NO) production induced by lipopolysaccharide in mouse macrophage RAW 264.7 cells in vitro with the IC₅₀ values which are comparable to hydrocortisone. Meanwhile, prenylated coumarins 1-12 exhibited considerable anti-HIV-1 reverse transcriptase (RT) activities possessing EC₅₀ values in the range of 0.17-9.08 µM. These findings indicate that the isolation and identification of these prenylated coumarins with pronounced anti-inflammatory effects as well as anti-HIV activities separated from the stems of C. lenis could be of great significance to the development of new anti-inflammatory and anti-HIV agents and their potential applications in the pharmaceutical industry.

Anti-inflammatory steroids from the fruits of Artocarpus heterophyllus

A phytochemical study on the fruits of Artocarpus heterophyllus caused the isolation of a previously undescribed steroid, artoheterophoid (1), together with seven known analogues (2 - 8). The chemical structure of 1 was elucidated on the basis of comprehensive spectroscopic methods and the known compounds (2 - 8) were identified by comparing their spectroscopic data with those reported in the literatures. All known compounds (2-8) were separated from A. heterophyllus for the first time. All isolated compounds (1-8) were assessed for their anti-inflammatory activities in vitro by measuring the inhibitory effect against nitric oxide (NO) production induced by lipopolysaccharide in mouse macrophage RAW 264.7 cells. Compounds 1-8 displayed remarkable inhibitory effects against NO production with the IC₅₀ values in the range of 0.72 ± 0.07 to 5.93 ± 0.12 μM.

Prenylated Coumarins from the Fruits of Manilkara zapota with Potential Anti-inflammatory Effects and Anti-HIV Activities

Manilkara zapota, usually known as Sapodilla, is a fairly slow-growing evergreen tropical tree which belongs to the genus Manilkara (Sapotaceae), indigenous to Central America, southern Mexico, and the Caribbean. The ripe fruits of M. zapota have been widely consumed as an uniquely flavored tropical fruit and verified to hold a variety of health benefits. In order to investigate the potential health-promoting chemical compositions from the fruits of M. zapota cultivated in Hainan Island of China, a systematic and in-depth phytochemical study on this fruit was accordingly implemented. In our current study, three new prenylated coumarins, manizapotins A-C (1-3), together with seven known prenylated coumarins (4-10), were separated from the fruits of M. zapota. The chemical structures of new prenylated coumarins 1-3 were unambiguously established by means of comprehensive spectroscopic analyses, and the known compounds 4-10 were determined by comparing their experimental spectral data with those described data in the literature. This is the first time to discover prenylated coumarins occurring in M. zapota. The potential anti-inflammatory effects and anti-HIV (human immunodeficiency virus) activities of all these separated prenylated coumarins were assessed. Prenylated coumarins 1-10 dispalyed remarkable inhibitory effects against nitric oxide production induced by lipopolysaccharide in mouse macrophage RAW 264.7 cells with the IC₅₀ values equivalent to that of hydrocortisone in vitro. Meanwhile, prenylated coumarins 1-10 exhibited pronounced anti-HIV-1 reverse transcriptase activities with the EC₅₀ values in range of 0.12-8.69 μM. These results suggest that appropriate and reasonable consumption of the fruits of M. zapota might assist people to prevent and reduce the occurrence of inflammatory diseases together with the infection of HIV. Furthermore, the discovery of these prenylated coumarins from the fruits of M. zapota holding pronounced anti-inflammatory effects along with anti-HIV activities could be of great significance to the research and development of new natural anti-inflammatory and anti-HIV agents.

Carbazole Alkaloids with Potential Neuroprotective Activities from the Fruits of Clausena lansium

Clausena lansium, also known as wampee, is a species of strongly scented evergreen trees belonging to the genus Clausena (Rutaceae), which is native to southern China. Its ripe fruits have been consumed as a very popular fruit and reported to possess a range of biological activities. To study the potential health-promoting constituents from the fruits of C. lansium, a chemical investigation on its fruits was thus carried out. In this study, 16 carbazole alkaloids (1-16), including six new carbazole alkaloids, clausenalansines A-F (1-6), were separated from the fruits of C. lansium. The molecular structures of these isolated new carbazole alkaloids (1-6) were ambiguously established on the basis of comprehensive spectroscopic methods. The known analogues (7-16) were determined via comparing their experimental data with those described in the literature, which were separated from C. lansium for the first time. All these isolated alkaloids were tested in vitro for their neuroprotective effects against 6-hydroxydopamine induced cell death in human neuroblastoma SH-SY5Y cells. Carbazole alkaloids 1-16 displayed remarkable neuroprotective effects possessing the EC₅₀ values ranging from 0.36 ± 0.02 to 10.69 ± 0.15 μM. These findings indicate that regular consumption of the fruits of C. lansium may help people prevent the occurrence of Parkinson's disease. In addition, the separation and identification of these carbazole alkaloids possessing remarkable neuroprotective effects from the fruits of C. lansium could be extremely important to the discovery of new agents for the prevention and treatment of Parkinson's disease.

Anti-Inflammatory and Antiproliferative Prenylated Isoflavone Derivatives from the Fruits of Ficus carica

Ficus carica is an Asian species of flowering plant belonging to the genus Ficus of the family Moraceae, native to Western Asia and the Middle East. Its fruits, usually known as common fig or fig, have been consumed as a very popular health-promoting fruit worldwide since ancient times. To investigate the potential health-promoting chemical constituents of the fruits of F. carica, a systematic phytochemical study on its fruits was therefore carried out. In our study, four new structurally diverse prenylated isoflavone derivatives, ficucaricones A-D (1-4), along with 12 known analogues (5-16) were separated from the fruits of F. carica. Their chemical structures were ambiguously elucidated based on extensive spectroscopic methods. The anti-inflammatory effects and antiproliferative activities of these isolated prenylated isoflavone derivatives were tested. Prenylated isoflavone derivatives (1-16) displayed remarkable inhibitory effects against nitric oxide (NO) production with the IC₅₀ values ranging from 0.89 ± 0.05 to 8.49 ± 0.18 μM, comparable to that of the positive control (hydrocortisone). Furthermore, compounds 1-16 also exhibited pronounced antiproliferative activities against diverse human cancer cell lines in vitro, holding the IC₅₀ values ranging from 0.18 ± 0.03 to 18.76 ± 0.09 μM. These findings indicate that regular consumption of the fruits of F. carica may help to prevent the occurrence of inflammatory diseases and tumors. Moreover, the isolation and characterization of these prenylated isoflavone derivatives possessing remarkable anti-inflammatory effects and antiproliferative activities could be meaningful to the discovery of new anti-inflammatory and antitumor agents.

Bisabolane sesquiterpenes from Clausena sanki with their potential anti-inflammatory activities

The investigation on the stems and leaves of Clausena sanki led to the isolation of a previously undescribed bisabolane sesquiterpene, clausemargic A (1), together with six known analogues (2-7). The structure of 1 was elucidated by extensive spectroscopic methods and the known compounds were identified by comparisons with data reported in the literature. All known compounds (2-7) were isolated from C. sanki for the first time. All isolated compounds were evaluated for their anti-inflammatory activities via examining the inhibitory activity on nitric oxide (NO) production induced by lipopolysaccharide in mouse macrophage RAW 264.7 cells in vitro. Compounds 1-7 showed significant inhibitory activities with IC₅₀ values comparable to that of hydrocortisone.