LC-MS Identification, Isolation, and Structural Elucidation of Anti-HIV Tigliane Diterpenoids from Wikstroemia lamatsoensis

Wikstroemia: A Review on its Phytochemistry and Pharmacology

BACKGROUND

Wikstroemia (the family Thymelaeaceae) consists of medicinal plants which established great value in traditional medicines for many years. For instance, W. indica is always recommended for treatments of syphilis, arthritis, whooping cough, and cancer. No systematic review of bioactive compounds from this genus has been recorded to date.

OBJECTIVES

The objective of the current study is to review phytochemical investigations and pharmacological effects of Wikstroemia plant extracts and isolates.

METHODS

By searching on the internet, the relevant data about Wikstroemia medicinal plants were retrieved from internationally renowned scientific databases, such as Web of Science, Google Scholar, Sci-Finder, Pubmed, and so on.

RESULTS

More than 290 structurally diverse metabolites were separated and identified from this genus. They include terpenoids, lignans, flavonoids, coumarins, mono-phenols, diarylpentanoids, fatty acids, phytosterols, anthraquinones, and others. Pharmacological records indicated that Wikstroemia plant crude extracts and their isolated compounds bring out various beneficial effects, such as anticancer, antiinflammatory, anti-aging, anti-viral, antimicrobacterial, antimalarial, neuroprotective, and hepatoprotective activities.

CONCLUSION

Wikstroemia has been regarded as a worthy genus with numerous phytochemicals and various pharmacological potentials. Modern pharmacological studies have successfully provided evidence for traditional uses. Nonetheless, their action mechanisms need to be further investigated. Although various secondary metabolites were identified from Wikstroemia plants, the current pharmacological research mainly concentrated on terpenoids, lignans, flavonoids, and coumarins.

LC-MS identification, isolation, and structural elucidation of anti-HIV macrocyclic daphnane orthoesters from Edgeworthia chrysantha

The occurrence of macrocyclic daphnane orthoesters (MDOs) with a 1-alkyl group originating from a C14 aliphatic chain is extremely limited in the plant kingdom and has only been isolated from Edgeworthia chrysantha. In the present study, LC-ESI-MS/MS analysis was performed on different parts of E. chrysantha, including flower buds, flowers, leaves, and stems, and resulted in the identification of seven MDOs in all the four plant parts, including two previously unreported compounds 1 and 7. Further LC-MS guided isolation was carried out to afford compounds 1 and 7, and their structures were determined by various spectroscopic analyses. These compounds were also evaluated for anti-HIV activity, thus expanding insights into the structure-activity relationships for MDOs.

Tigliane and daphnane diterpenoids from Thymelaeaceae family: chemistry, biological activity, and potential in drug discovery

Tigliane and daphnane diterpenoids are characteristically distributed in plants of the Thymelaeaceae family as well as the Euphorbiaceae family and are structurally diverse due to the presence of polyoxygenated functionalities in the polycyclic skeleton. These diterpenoids are known as toxic components, while they have been shown to exhibit a wide variety of biological activities, such as anti-cancer, anti-HIV, and analgesic activity, and are attracting attention in the field of natural product drug discovery. This review focuses on naturally occurring tigliane and daphnane diterpenoids from plants of the Thymelaeaceae family and provides an overview of their chemical structure, distribution, isolation, structure determination, chemical synthesis, and biological activities, with a prime focus on the recent findings.

Daphnepedunins A-F, Anti-HIV Macrocyclic Daphnane Orthoester Diterpenoids from Daphne pedunculata

From the whole plant of Daphne pedunculata, 12 macrocyclic daphnane diterpenoids, including six new compounds, daphnepedunins A-F (1-4, 9, and 10), were isolated. Their structures were elucidated by physiochemical and spectroscopic data analysis, the modified Mosher's method, and X-ray crystallography. The isolated compounds were evaluated for anti-HIV activity against HIV-1 infection in MT4 cells and showed significant anti-HIV activity with IC₅₀ values of 36.3-994 nM. A consideration of the anti-HIV activity of these compounds provided further insight into the structure-activity relationships of macrocyclic daphnane diterpenoids.

Targeted isolation of diterpenoids and sesquiterpenoids from Daphne gemmata E. Pritz. ex Diels using molecular networking together with network annotation propagation and MS2LDA

Investigation of the whole plant of Daphne gemmata E. Pritz. ex Diels (Thymelaeaceae) using molecular networking coupled to Network Annotation Propagation (NAP) and unsupervised substructure annotation (MS2LDA) led to the discovery of five tigliane diterpenoids, 14 guaiane sesquiterpenoids, one rhamnofolane diterpenoid and three carotene sesquiterpenoids. The structures of the eight undescribed compounds, daphnorbol A and daphnegemmatoids A-G, were characterized by detailed spectroscopic analyses, NMR and ECD calculations, application of Snatzke's method and single-crystal X-ray diffraction analysis. All isolated compounds were evaluated for their cytotoxic activities against HepG2, A549, and MCF-7 cells by MTT assay. Daphnorbol A exhibited significant cytotoxic activity against HepG2 and A549 cells with IC50 values of 4.06 μM and 6.35 μM, respectively. Prostratin showed potent cytotoxic activity against HepG2 and A549 cells with IC50 values of 6.06 μM and 5.45 μM, respectively. Further Hoechst 33,258 and AO-EB staining assays indicated that daphnorbol A and prostratin could induce apoptosis in HepG2 and A549 cells.

Lead/Drug Discovery from Natural Resources

Natural products and their derivatives have been shown to be effective drug candidates against various diseases for many years. Over a long period of time, nature has produced an abundant and prosperous source pool for novel therapeutic agents with distinctive structures. Major natural-product-based drugs approved for clinical use include anti-infectives and anticancer agents. This paper will review some natural-product-related potent anticancer, anti-HIV, antibacterial and antimalarial drugs or lead compounds mainly discovered from 2016 to 2022. Structurally typical marine bioactive products are also included. Molecular modeling, machine learning, bioinformatics and other computer-assisted techniques that are very important in narrowing down bioactive core structural scaffolds and helping to design new structures to fight against key disease-associated molecular targets based on available natural products are considered and briefly reviewed.

Anti-HIV Tigliane-Type Diterpenoids from the Aerial Parts of Wikstroemia lichiangensis

Tigliane-type diterpenoids have attracted much attention in drug discovery since they have been reported to exhibit remarkable biological effects, such as tumor-promoting, antineoplastic, and anti-HIV activities. In continuing our efforts to discover novel biologically important diterpenoids from Wikstroemia species, Wikstroemia lichiangensis was investigated phytochemically for the first time. As a result, four new (1-4) and one known (5) tigliane-type diterpenoid were isolated, and their structures were elucidated by spectroscopic data analysis. Tiglianes (1-5) showed potent anti-HIV activity against HIV-1 infection of MT4 lymphocytes with IC₅₀ values of 1.1-65.4 nM.

Characteristic biflavonoids from Daphne kiusiana var. atrocaulis (Rehd.) F. Maekawa

Structurally diverse biflavonoids have attracted significant research interest for drug discovery over past decades. Biflavonoid oriented phytochemistry research on the stems of Daphne kiusiana var. atrocaulis (Rehd.) F. Maekawa was carried out, which resulted in the identification of ten major effective components (1-10), including the undescribed biflavonoids, daphnodorin Q (1), daphnodorin R (2) and flavane, daphnekiuslin A (10). The known structures were identified from this herb for the first time. Their structures were determined by combination of multiple spectroscopic data as well as calculated electronic circular dichroism (ECD). All the identified compounds were evaluated for the anti-neuroinflammatory effects. Compound 9 could inhibit the overactivation of BV-2 cells induced by lipopolysaccharide with IC₅₀ value at 26.32 μM.