A Comprehensive Review on Pharmacologically Active Phyto-Constituents from Hedychium species.

In this review, we describe and discuss the phytoconstituents present in Hedychium species and emphasize their potential as drug candidates. Though they are widely validated in vitro and in vivo models, to date, no efforts have been made to compile in a single review all the pharmacologically active phytoconstituents from Hedychium species, and their pharmacological and toxicity profile. In this study, we present a reinvestigation of the chemical constituents present in Hedychium species obtained from the essential oil and solvent extraction of the flowers, leaves and rhizomes under consideration. Key databases such as PubMed, Science Direct, Scopus, and Google Scholar amongst others were probed for a systematic search using keywords to retrieve relevant publications on this plant. An exhaustive electronic survey of the related literature on Hedychium species resulted in around 200 articles. Articles published between the years 1975-2021 were included. The studies conducted on either crude extracts, solvent fractions or isolated pure compounds from Hedychium species reported with a varied range of biological effects such as anti-inflammatory, analgesic, antidiabetic, potentially anti-asthmatic, and cytotoxic, among other related activities of the chemical constituents present in its essential oil and solvent extract deployed in this review. Traditional and herbal medication around the world that uses different parts of Hedychium species were considered for anti-inflammatory, skincare, analgesic, anti-asthmatic, anti-diabetic, antidotal uses, among others. These uses support the idea that chemical constituents obtained from solvent extraction may also exert the same action individually or in a synergistic manner. The review concluded that there is scope for computation and biological study to find out possible new targets for strengthening the potency and selectivity of the relevant compounds, and to find a commercial method for extraction of active pharmaceutical ingredients.

Natural Compounds with BMI1 Promoter Inhibitory Activity from Mammea siamensis and Andrographis paniculata.

A new coumarin derivative (1) and 30 known compounds were isolated from Mammea siamensis and Andrographis paniculata, guided by B cell-specific Moloney murine leukemia virus insertion region 1 (BMI1) promoter inhibitory activity. Among the isolated compounds, 15 compounds showed BMI1 promoter inhibitory activity, and five compounds were found to be cytotoxic. 14-Deoxy-11,12-dehydroandrographolide (18) was highly cytotoxic to DU145 cells with an IC50 value of 25.4 µM. Western blotting analysis of compound 18 in DU145 cells suggested that compound 18 suppresses BMI1 expression.

Investigation on the antimicrobial activities of gingers (Etlingera coccinea (Blume) S.Sakai & Nagam and Etlingera sessilanthera R.M.Sm.) endemic to Borneo.

AIMS: To investigate the antimicrobial properties of Etlingera coccinea and Etlingera sessilanthera and to isolate and identify the antimicrobial compounds. METHODS AND RESULTS: Extracts were obtained via sequential solvent extraction method using hexane, dichloromethane, ethyl acetate, methanol and water. Antimicrobial activity testing was done using broth microdilution assay against 17 strains of bacteria. The leaf hexane extract of E. coccinea and rhizome hexane extract of E. sessilanthera showed best antimicrobial activities, with minimum inhibitory concentration (MIC) values ranging from 0·016 to 1 mg ml-1 against Gram-positive bacteria. From these active extracts, two antimicrobials were isolated and identified as trans-2-dodecenal and 8(17),12-labdadiene-15,16-dial with MIC values ranging from 4 to 8 µg ml-1 against Bacillus cereus, Bacillus subtilis and Staphylococcus aureus. CONCLUSION: Etlingera coccinea and E. sessilanthera demonstrated good antimicrobial activities against clinically relevant bacteria strains. The antimicrobial compounds isolated showed low MIC values, hence suggesting their potential use as antimicrobial agents. SIGNIFICANCE AND IMPACT OF THE STUDY: This study is the first to identify the potent antimicrobials from these gingers. The antimicrobials isolated could potentially be developed further for use in treatment of bacterial infections. Also, this study warrants further research into other Etlingera species in search for more antimicrobial compounds.

Labdane Diterpenes from the Fruits of Sinopodophyllum emodi.

Two new labdane diterpenes, sinoditerpene A (1) and B (2), were isolated from the fruits of Sinopodophyllum emodi, along with two known analogues 3 and 4. Their structures were established on the basis of extensive spectroscopic analysis. The isolation of compounds 1-4 represents the first report of diterpenes from the genus Sinopodophyllum. The cytotoxic activities of all isolated compounds were evaluated in comparison with 5-fluorouracil against the MCF-7 and HepG2 cell lines, towards which 3 showed more potent cytotoxicity.

Synthesis of new ent-labdane diterpene derivatives from andrographolide and evaluation on cytotoxic activities.

There are many reports for andrographolide modification regarding antitumor effects. Transformation of the five-membered lactone ring to furan aromatic ring still results in compounds with good cytotoxicity. To determine further the importance of the five-membered lactone ring and to obtain better lead compounds, we transformed the five-membered lactone ring in andrographolide. New types of ent-labdane diterpene derivatives were made, whose cytotoxic activities were measured in vitro. Preliminary SAR was summarized and two compounds, 7 and 26, with good cytotoxic activity were obtained, which have the potential to be developed into new antitumor drugs.

Inhibition of human neutrophil elastase by labdane diterpenes from the fruiting bodies of Ramaria formosa.

Two new labdane diterpenes (1 and 2) were isolated from the fruiting bodies of Ramaria formosa. The structures of these compounds were established by extensive spectroscopic studies and chemical evidence. The inhibitory activity of compounds 1 and 2 against human neutrophil elastase (HNE) was evaluated in vitro. Compounds 1 and 2 inhibited HNE activity moderately. The IC50 values for compounds 1 and 2 were 36.4 ± 1.2 and 40.8 ± 1.5 µM, respectively; the IC50 value for the positive control, EGCG, was 12.5 ± 0.8 µM. In addition, the mechanism by which 2 inhibited HNE was a mixed-type noncompetitive inhibition, with a Ki of 41.5 ± 1.8 µM.

Pahangensin A and B, two new antibacterial diterpenes from the rhizomes of Alpinia pahangensis Ridley.

The rhizomes of Alpinia pahangensis Ridley yielded a new bis-labdanic diterpene for which the name pahangensin A (1) was proposed along with a new labdane diterpene, pahangensin B (2). Their structures were elucidated by spectroscopic methods including, 1D and 2D NMR techniques and LCMS-IT-TOF analysis. Pahangensin A (1) was found to be an antibacterial agent against Staphylococcus aureus, Bacillus cereus and Bacillus subtilis with MIC values less than 100 µg/mL, respectively. Pahangensin B (2) exhibited antibacterial activity (MIC <100 µg/mL) against B. cereus.

Cathayanalactone G and other constituents from leaves and twigs of Callicarpa cathayana.

Objective: To study the chemical constituents from the leaves and twigs of Callicarpa cathayana. Methods: The chemical constituents were isolated and purified by column chromatography on silica gel, MCI gel CHP 20P/P120, Sephadex LH-20, and HPLC. The structures of the compounds were determined by HR-ESI-MS, 1D and 2D NMR data. Results: A total of 24 compounds were isolated from the 85% methanol extract of leaves and twigs of C. cathayana. They were identified as cathayanalactone G (1), a new diterpene, and 23 known compounds as patagonic acid (2), (-)-16-hydroxycledroda-3,13-dien-16,15-olide-18-oic acid (3), 15-methoxypatagonic acid (4), oleanolic acid (5), ursolic acid (6), siaresinolic acid (7), pomolic acid (8), α-amyrin (9), tormentic acid (10), lupeol (11), 5,7-dihydroxy-3,4'-dimethoxyflavone (12), 5,4'-dihydroxy-3,7,3'-dimethoxyfla-vone (13), 5-hydroxy-3,6,7,4'- tetramethoxyflavone (14), salvigenin (15), kaemferol (16), astragalin (17), pinoresinol 4-O-ß-D-glucopyranoside (18), paulownin (19), ß-sitosterol (20), ß-sitosterol ß-D-glucopyranoside (21), 5-hydroxy-coumarin (22), isocopoletin (23), and 4-hydroxycinnamic acid (24). Conclusion: Compound 1 is a new labdane diterpene. Compounds 10, 13, 16 and 17 are isolated from the genus Callicarpa for the first time. Compounds 7, 8, 9, 12, 14, 23 and 24 are reported from C. cathayana for the first time.

Semi-synthetic diversification of coronarin D, a labdane diterpene, under Ugi reaction conditions.

The prevalence of 5-hydroxydihydrofuran-2(3H)-one moiety in natural products is exploited for the first time using coronarin D, a labdane diterpene, to afford Ugi reaction product 1a and interrupted Ugi product 2a. The potential of the Ugi reaction was further extended to l-phenylalanine, 2-aminopyridine, and d-glucosamine, which afforded Ugi reaction products 3a-f, 4, and 5a-d, respectively. Cytotoxicity studies in RAW cells reveal that compounds 3e and 5b were non-toxic up to 50 µM, and these compounds were able to reduce the LPS stimulated NO production in RAW cells in par with the standard anti-inflammatory drug dexamethasone.

Therapeutic potential of labdane diterpene isolated from Alpinia nigra: detailed hemato-compatibility and antimicrobial studies.

(E)-labda-8(17), 12-diene-15,16-dial has been isolated from the seeds of Alpinia nigra that is unsuitable for oral administration and evident from in silico studies. The present investigation therefore deals with understanding the effect of this compound on RBCs for intravenous administration. No prominent hemolytic effect of compound at a concentration of ≤0.4 mg/ml was found whereas higher concentrations perforated RBC membrane. The molecule showed remarkable inhibitory potential against Gram negative bacteria (concentration ≥0.025 mg/ml) causing cell lysis. In case of pathogenic yeast Candida albicans although growth was inhibited (concentration ≥ 0.0025 mg/ml), growth kinetic study revealed that the diterpene significantly delayed fungal growth (concentration 0.005-0.020 mg/ml) by preventing substrate uptake and was able to extend its lag phase in a dose-dependent manner. This study tries to unveil the mechanism of action of this diterpene on microorganisms with differential cell wall compositions.

Crystal structure and Hirshfeld surface analysis of the methanol solvate of sclareol, a labdane-type diterpenoid.

The title compound, C20H36O2·CH3OH [systematic name: (3S)-4-[(S)-3-hy-droxy-3-methyl-pent-4-en-1-yl]-3,4a,8,8-tetra-methyl-deca-hydro-naphthalen-3-ol methanol monosolvate], is a methanol solvate of sclareol, a diterpene oil isolated from the medicinally important medicinal herb Salvia sclarea, commonly known as clary sage. It crystallizes in space group P1 (No. 1) with Z' = 2. The sclareol mol-ecule comprises two trans-fused cyclo-hexane rings, each having an equatorially oriented hydroxyl group, and a 3-methyl-pent-1-en-3-ol side chain. In the crystal, Os-H⋯Os, Os-H⋯Om, Om-H⋯Os and Om-H⋯Om (s = sclareol, m = methanol) hydrogen bonds connect neighboring mol-ecules into infinite [010] chains. The title compound exhibits weak anti-leishmanial activity (IC50 = 66.4 ± 1.0 µM ml-1) against standard miltefosine (IC50 = 25.8 ± 0.2 µM ml-1).

Anticancer activities and mechanism of action of the labdane diterpene coronarin D.

The anticancer properties of several labdane diterpenes have been well characterized, notably for andrographolide and sclareol. In contrast, the structurally related natural product coronarin D (CRD), principally isolated from the ginger Hedychium coronarium, is much less known. Recently, different studies have underlined the anticancer activities of CRD and in particular its capacity to inhibit the growth and to induce the death of glioblastoma and carcinoma cell lines in vitro. The present review provides a global view of the activities and mechanism of action of CRD and the analogy with the other anticancer labdane diterpenes. CRD exerts its antiproliferative action via an activation of the MAPK pathway, notably by a stimulation of ERK/JNK phosphorylation, which subsequently leads to drug-induced inhibition of cell proliferation and activation of the intrinsic apoptotic pathway. Reactive oxygen species also play a role in the bioactivity of drug, but no well-defined molecular target has been characterized yet. CRD presents an interesting activity profile in vitro and warrants in vivo evaluations, notably for the treatment of glioblastoma.

New Diterpenoids from the Aerial Parts of Salvia reuterana.

The genus Salvia is a valuable origin of structurally diverse terpenoids. In a project directed at structurally interesting bioactive metabolites from Iranian Salvia species, we studied Salvia reuterana. Two new labdane diterpene, 6ß, 14α-dihydroxy-15-acetoxysclareol (1), and 14α, 15- dihydroxy sclareol (2), were isolated from the aerial part of the plant. Their structures were established mainly by 1D and 2D NMR spectroscopic techniques, including 1H-1H COSY, HSQC and HMBC methods and HR-ESI-TOFMS spectral data. Compound 1 and 2 were tested for their inhibitory activity toward HeLa and MCF-7 cell lines. Our results showed that S. reuterana is a rich source of labdane diterpenoids. These compounds are rather rare in Salvia species, although they are frequently found in other genera of the Lamiaceae. S. reuterana is a new source of these diterpenoids.

Hedychium spicatum: a systematic review on traditional uses, phytochemistry, pharmacology and future prospectus.

OBJECTIVES: Hedychium spicatum Buch. Ham. ex D.Don. (Family Zingiberaceae) is a rhizomatous herb, used in medicines, food, cosmetics and perfumery industries. Traditionally, it is widely used in treating inflammation, pain, asthma, foul breath, vomiting, diarrhoea, bronchitis, hiccough and blood diseases. This study systematically reviewed traditional and folk uses, pharmacological properties, bioactive compounds and market potential of H. spicatum. Research gaps and potential of future research have also been discussed. KEY FINDINGS: Available literature indicates that research on this species is largely focused on phytochemical and pharmacological studies; however, propagation and modern interventions for high productivity have been contravened. These studies demonstrated that the rhizome of the species exhibited many valuable and medicinally important compounds, such as labdane terpenes, hedychinone and polyphenols. Many of the traditional uses of the species have been validated through the findings of pharmacological studies and biological properties of the extracts and pure compounds. Phytochemical constituents and related pharmacological activities have provided some suggestive scientific evidences for the various ethnomedicinal uses of the species in the treatment, control and management of diseases and for new drug discovery. SUMMARY: Literature reveals that the species is lacking in exact scientific basis of the beneficial properties. Although, some other distinct biological properties identified in this species also opened new door way for its new applications. Therefore, the mentioned phytochemical constituents such as phenolic and flavonoids compounds; and related pharmacological activities such as antimicrobial, anti-inflammatory and antioxidant activity of the species have provided some suggestive scientific evidences for its potential in pharmaceutical, food and aromatic industries.

A new labdane diterpene from the rhizomes of Alpinia officinarum.

A new labdane diterpene, (Z)-12,14-labdadien-15(16)-olide-17-oic acid (1), and a new natural cadinane sesquiterpene, 4-isopropyl-6-methyl-1-naphthalenemethanol (2), were isolated from the ethanolic extract of the rhizomes of Alpinia officinarum, together with three other products, galangin (3), kaempferol (4) and quercetin (5). Their structures were elucidated by using extensive spectroscopic methods. Compounds 1 and 2 showed no remarkable cytotoxic activity against HeLa and HepG2 cancer cell lines with IC50>50 µg mL(- 1).

Retraction. A new antifungal labdane diterpene from the leaves of Saraca indica.

A new labdane diterpene, along with 10 known sterols and flavonoids, was isolated from the hydroalcoholic extract of the leaves of Saraca indica. The chemical structure of the new compound was identified as 6,9-epoxy marrubiinic acid on the basis of spectroscopic analyses including two-dimensional NMR. The antimicrobial potential of the new compound was evaluated against Gram-positive and Gram-negative bacteria as well as fungi. It showed a significant antifungal activity against Geotrichum candidum with MIC 0.48 µg/mL. It also showed potential cytotoxicity against human cancer cell lines with IC50 ranging from 1.07 to 1.29 µg/well.

Suppression of nuclear factor-kappa B and mitogen-activated protein kinase signalling pathways by goshonoside-F5 extracted from Rubi Fructus.

Rubi Fructus, a traditional Chinese medicine, was considered as an anti-inflammatory agent in folk medicine. In the present study, we investigated the signalling pathways involved in the anti-inflammatory effects of goshonoside-F5 (GF5), isolated from Rubi Fructus, in peritoneal macrophages and examined its therapeutic effect in a mouse endotoxic shock model. GF5 decreased NO and PGE2 production in LPS-stimulated macrophages (IC50=3.84 and 3.16µM). This effect involved the suppression of NOS-2 and COX-2 gene expression at the transcriptional level. Examination of the effects of GF5 on NF-κB signalling demonstrated that it inhibits the phosphorylation of IκB-α and IκB-ß, blocking their degradation and the nuclear translocation of the NF-κB p65 subunit. Moreover, inhibition of MAPK signalling was also observed, and phosphorylation of p38 and JNK was suppressed in the presence of GF5. Inflammatory cytokines, including IL-6 and TNF-α, were down-regulated by this compound after activation with LPS (IC50=17.04 and 4.09µM). Additionally, GF5 (30 and 90mg/kg, i.p.) significantly reduced the circulating cytokine levels (IL-6 and TNF-α) and increased survival in a mouse model of endotoxemia. These results show that GF5 significantly inhibits the pro-inflammatory response induced by LPS, both in vitro and in vivo. Our results provide a strong pharmacological basis for further understanding the potential therapeutic role of GF5 in inflammatory disease and shed new light on the bioactivity of ent-labdane diterpene glucoside.

Unveiling the mode of action of antibacterial labdane diterpenes from Alpinia nigra (Gaertn.) B. L. Burtt seeds.

The labdane diterpene, (E)-labda-8(17), 12-diene-15, 16-dial (compound A) and its epoxide analogue, (E)-8ß, 17-Epoxylabd-12-ene-15, 16-dial (compound B) were isolated from the seeds of Alpinia nigra for the first time. The antibacterial activities of both compounds were evaluated against three Gram-positive and four Gram-negative bacteria, and flow cytometric analysis revealed that these compounds caused significant damage to the bacterial cell membranes. Further, field emission scanning electron microscope imaging and cell leakage analysis confirmed that the labdane diterpenes were responsible for bacterial cell membrane damage and disintegration. Our findings provide new insight into the broad-spectrum effects of two natural labdane diterpenes that may be useful in the future development of herbal antibiotic products.

Labdane diterpenes from Chloranthus serratus.

Five new labdane diterpenes (1-5), serralabdanes A-E, were isolated from the whole plant of Chloranthus serratus. Their structures were elucidated by spectroscopic methods, and the absolute configuration of the 12,13-diol moiety in serralabdane C (3) was determined by observing the induced circular dichroism (ICD) after addition of dimolybdenum teracetate in DMSO solution. Serralabdanes A-E (1-5) showed inhibitory effects on lipopolysaccharide-induced nitric oxide production in RAW264.7 cells.