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

Diterpenes as nitric oxide secretion inhibitors from Kaempferia koratensis rhizomes

Kaempferia koratensis Picheans. (Zingiberaceae), known locally as "Proa Korat" or "Wan Proa Khao," is native to northeastern Thailand where it is widely used for its aromatic properties in the local cuisine. Given its potential for expanded applications in traditional medicines, and for foods and food supplements derived from certain Kaempferia species, this study focused on the metabolites of K. koratensis rhizomes and evaluated their in vitro anti-inflammatory properties. Eight new isopimarane diterpenoids were isolated, including five koratones A-E, two koratanes C and D, and a bisditerpenoid, named as koratensin, together with six known isopimarane diterpenoids. The anti-inflammatory properties were evaluated by inhibiting nitric oxide production, with curcumin used as a positive control. The results revealed that koratone B was the most potent isolate at 25 μg/mL with 36.54 ± 0.79 % inhibition and koratane D at 50 μg/mL with 58.85 ± 4.12 % inhibition. Molecular docking of koratone B suggested the inhibitory effect was due to an affinity for hydrogen bonding at the active site of iNOS. The physicochemical and pharmacokinetic properties of koratone B were calculated. These findings indicate that selected isopimarane diterpenoids from K. koratensis, such as koratone B, merit further developmental consideration to potentiate the observed biological response.

Anti-Neuroinflammatory Labdane Diterpenoids From the Rhizomes of Alpinia zerumbet

Alpinia zerumbet, commonly known as shell ginger, is a plant of significant ornamental and medicinal value. In the present study, nine labdane-type diterpenoids, including four novel (1-4) and five known (5-9), were isolated and identified from the rhizomes of A. zerumbet. Anti-neuroinflammatory activities of the isolated labdane-type diterpenoids were evaluated in lipopolysaccharide (LPS)-stimulated microglia BV2 cells. Compounds 3, 5, 6, and 8 could significantly inhibit the production of nitric oxide (NO) in LPS-stimulated BV2 cells. Among them, the IC50 values of compounds 5 and 8 were 26.14 ± 1.62 and 17.29 ± 6.28 µM, which were lower than that of the positive control, minocycline (IC50 = 30.26 ± 1.99 µM).

Bi- and tricyclic diterpenoids: landmarks from a decade (2013-2023) in search of leads against infectious diseases

Covering: 2013 to 2023In an era where antimicrobial resistance severely threatens our ability to treat infections, the discovery of new drugs that belong to different chemical classes and/or bear original modes of action is urgently needed. In this case, diterpenoids comprise a productive field with a proven track record in providing new anti-infectives to tackle bacterial infections and malaria. This review highlights the potential of both naturally occurring and semi-synthetic bi- and tricyclic diterpenoids to become leads in search of new drugs to treat infections caused by bacteria, fungi, viruses and protozoan parasites. The literature from the last decade (2013-2023) is covered, focusing on naturally occurring and semi-synthetic bicyclic (labdanes and labdane-type) and tricyclic (all classes) diterpenoids, detailing their relevant biological activities in the context of infection, which are explained through structure-activity relationships.

Preparation and antibacterial activity of coronarin E derivatives

Coronarin E is a main diterpene ever isolated from Hedychium yunnanense. With the aim to enlarge its potential application, four butenolide derivatives (compounds 4a, 4b, 5a and 5b) were obtained from coronarin E via synthetic method, and their antibacterial effects were also evaluated. It is noteworthy that compounds 5a and 5b exhibited stronger antibacterial activities against most of the tested bacterial strains than ampicillin and kanamycin, two first- and second-line antimicrobials in clinical. For example, minimum inhibitory concentration (MIC) of 5a, 5b, ampicillin and kanamycin against Acinetobacter baumanii were 2, 1, 8 and 4 μg/mL, respectively, and MIC of the four compounds mentioned above against Klebsiella pneumonia were 1, 0.5, 16 and 4 μg/mL, respectively. The current studies not only enrich the structural diversity of diterpenes derived from Hedychium genus, but also provide potent candidates for the development of antibacterial medicines.

Anti-Inflammatory Terpenoids from the Rhizomes of Shell Ginger

Shell ginger (Alpinia zerumbet) is a perennial ornamental plant of ginger native to East Asia, which can be used as a flavoring agent in food or beverage, as well as a traditional Chinese medicine. In this study, a total of 37 terpenoids, including 7 new compounds, zerumin D1 to zerumin D7 (2, 3, 28-30, 36, and 37), and 5 new naturally occurring compounds, zerumin D10 to zerumin D14 (9, 12, 15, 20, and 24), were isolated and identified from the rhizomes of shell ginger. Compound 3 was an unprecedented variant labdane diterpenoid featuring a unique 6/7/6/3 tetracyclic cyclic ether system in its side chain. The anti-inflammatory activities of the isolated terpenoids were assessed in RAW 264.7 macrophages stimulated by lipopolysaccharide (LPS). Compound 4 significantly inhibited the production of nitric oxide with an IC50 value of 5.4 μM. Further investigation revealed that compounds 2 and 3 may inhibit the nuclear translocation of NF-κB, thus suppressing the expression of IL-6, IL-1β, iNOS, and COX-2 to exert the anti-inflammatory effects.

Biogenetic and biomimetic synthesis of natural bisditerpenoids: hypothesis and practices

Covering: up to March 2022Bisditerpenoids, or diterpenoid dimers, are a group of natural products with high structural variance, deriving from homo- or hetero-dimeric coupling of two diterpenoid units. They usually possess complex architectures resulting from the diversity of monomeric diterpenoids as building blocks and the dimerization processes. These compounds have attracted the attention of synthetic and biological scientists owing to the rarity of their natural origin and their significant biological activities. Herein, we provide a review highlighting some of the interesting bisditerpenoids reported since 1961 and showcase the chemical diversity in both their structures and biosynthesis, as well as their biological functions. This review focuses on the biosynthetic dimerization pathways of interesting molecules and their biomimetic synthesis, which may act as useful inspiration for the discovery and synthesis of more bisditerpenoids and further pharmacological investigations.

Docking Study on Anti-HIV-1 Activity of Secondary Metabolites from Zingiberaceae Plants

Introduction:

Human immunodeficiency virus type-1 (HIV-1) that causes acquired immunodeficiency syndrome (AIDS) has become a worldwide health problem today. There are approximately 30 anti-HIV-1 drugs that have been used in the treatment of AIDS. However, effective anti HIV-1 agents with less side affect and high inhibition potency are still in demand.

Objective:

The objective of this study was to identify the potential compounds from Zingiberaceae plants that might be active as anti-HIV-1 by molecular docking.

Materials and Methods:

Molecular docking simulation was performed by using AutoDock 4.2 on Linux operation system. Docking protocol was validated by using root mean square deviation (RMSD) value using redocking and cross-docking methods. The reported metabolites from Zingiberaceae plants were docked on HIV-1 protease, integrase, and reverse transcriptase protein enzymes.

Results:

The docking result showed that the genera of Zingiber, Etlingera, Alpinia, Hedychium, and Boesenbergia have potential metabolites that inhibit HIV protease, integrase, and reverse transcriptase enzymes by possessing lower docking energy than native ligand of amprenavir, raltegravir, and nevirapine. Among the metabolites, noralpindenoside B and alpindenoside A from Alpinia densespicata inhibited protease enzymes with the lowest docking energy of -18.02 and -17.90 kcal/mol, respectively. Meanwhile, panduratin E from Boesenbergia pandurata Roxb. and 5α,8α-epidioxyergosta-6,22-dien-3β-ol from Etlingera elatior showed the lowest docking energy on integrase protein with docking energy of -11.97 and -11.41 kcal/mol, respectively. Pahangensin A from Alpinia pahangensis Ridley showed the lowest docking energy on reverse transcriptase enzyme with docking energy of -13.76 kcal/mol.

Conclusion:

The docking molecular study has identified the possible potential compounds from Zingiberaceae plants that might be used for anti-HIV-1 treatment. So, this study suggested further isolation and purification of the predicted compounds.

Anti-Vpr activities of homodrimane sesquiterpenoids and labdane diterpenoids from Globba sherwoodiana rhizomes

Two new homodrimane sesquiterpenoids, globbatones A and B (1 and 2), and one 16-norlabdane diterpenoid, globbatone C (3), together with two new naturally occurring, (E)-labda-8(17),12-diene-15,16-olide (4) and γ-bicyclohomofarnesen-12-ol (5), and one known homodrimane sesquiterpenoid (6), nine known labdane diterpenoids (7-15), and one isospongian diterpenoid (16), were isolated from the chloroform extract of Globba sherwoodiana rhizomes. The structures of the new compounds 1-3 were elucidated based on 1D and 2D NMR and HRESIMS spectroscopic analyses. The chloroform extract of G. sherwoodiana rhizomes and 10 μM concentrations of some of its constituents 1, 3, 4, 8, 9, 12, and 14 showed the moderate anti-Vpr activities, without cytotoxic effects on the TREx-HeLa-Vpr cell line.

Molecular Insight and Mode of Inhibition of α-Glucosidase and α-Amylase by Pahangensin A from Alpinia pahangensis Ridl

The inhibition of carbohydrate-hydrolyzing enzymes in human digestive organs is crucial in controlling blood sugar levels, which is important in treating type 2 diabetes. In the current study, pahangensin A (1), a bis-labdanic diterpene characterized previously in the rhizomes of Alpinia pahangensis Ridl., was identified as an active dual inhibitor for α-amylase (IC₅₀ =114.80 μm) and α-glucosidase (IC₅₀ =153.87 μm). This is the first report on the dual α-amylase and α-glucosidase inhibitory activities of a bis-labdanic diterpene. The Lineweaver-Burk plots of compound 1 indicate that it is a mixed-type inhibitor with regard to both enzymes. Based on molecular docking studies, compound 1 docked in a non-active site of both enzymes. The dual inhibitory activity of compound 1 makes it a suitable natural alternative in the treatment of type 2 diabetes.

An overview of chemical constituents from Alpinia species in the last six decades

Alpinia species is one of the most important genera of the Zingiberaceae family. Up to 2015, 544 compounds with various bioactivities were isolated, the major components are diarylheptanoids (143) and sesquiterpenoids (132).

Therapeutic Potential of Essential Oils Focusing on Diterpenes

Among all plant derivates, essential oils (EOs) have gained the attention of many scientists. Diterpenes, a family of components present in some EO, are becoming a milestone in the EOs world. The goal of this review is to describe a scenario of diterpenes taking into health-consumption deportment. Previous studies revealed that diterpenes have antioxidant, antimicrobial, antiviral, antiprotozoal, cytotoxic, anticancer, antigenotoxic, antimutagenic, chemopreventive, antiinflammatory, antinociceptive, immunostimulatory, organoprotective, antidiabetic, lipid-lowering, antiallergic, antiplatelet, antithrombotic, and antitoxin activities. In conclusion, diterpenes may be an immense featuring concern in pharmaceutical consumption from a drug discovery point of view. Copyright © 2016 John Wiley & Sons, Ltd.

Diterpenoids of terrestrial origin

This review covers the isolation and chemistry of diterpenoids from terrestrial as opposed to marine sources and includes labdanes, clerodanes, pimaranes, abietanes, kauranes, gibberellins, cembranes and their cyclization products. The literature from January to December 2013 is reviewed.