Genus Gelsemium and its Endophytic Fungi - Comprehensive Review of their Traditional Uses, Phytochemistry, Pharmacology, and Toxicology.

BACKGROUND: The use of ethnic medicinal plants has revitalized wide popularity in Africa, Asia, and most of the world because of the energy consumption barriers increase of synthetic drugs. Gelsemium is a traditional genus of plants with famous cultural and medicinal significance in Southeast Asia and North America. Three species are reported from the genus Gelsemium, including Gelsemium elegans (Gardn. & Camp.) Benth., Gelsemium sempervirens (L.) J.St.-Hil., and Gelsemium rankinii Small. Among them, G. elegans is well known for its toxicity and is used as a traditional remedy for skin problems, neuralgia, fractures, and cancer. The first record of the toxic medicine G. elegans is the Chinese herbal medicine classically known as Shen-Nong Ben-Cao Jing. In the legend, the Shennong emperor was poisoned by G. elegans, hence, it is also wellknown as Duan Chang Cao in China. In addition, G. sempervirens tincture is also used in the treatment of inflammation of the spinalcolumn, and diminishes blood to the cerebrospinal centers. INTRODUCTION: This review aims to provide up-to-date information on Gelsemium and its endophytic fungi on their traditional uses, phytochemistry, pharmacology, and toxicology. Mechanism studies regarding the detoxification profile of Gelsemium are also reviewed. METHODS: For this updated review, the literature survey and search were performed on the scientific databases PubMed, ScienceDirect, Wiley, China CNKI, Web of Science, SciFinder, and Google Scholar using the relevant keywords. RESULTS: The plants of the genus Gelsemium are all reported as rich sources of monoterpene indole alkaloids. Previous phytochemical studies published more than 200 alkaloids from Gelsemium and its endophytic fungi, which have attracted considerable attention from pharmaceutists and phytochemists due to their diverse and complex structures. The bioactivities of Gelsemium phytoconstituents studied using various chemical methods are summarized and described herein. Considering the huge influence of Gelsemium regarding its traditional applications, the activities of isolated compounds were focused on the anti-tumor, anti-inflammatory, analgesic and antianxiety, immunostimulatory, and immunosuppressive properties, which provide evidence supporting the ethnopharmacological effectiveness of the genus Gelsemium. Unlike all previous reviews of genus Gelsemium, to the best of our knowledge, the recently reported natural products from its endophytic fungi are first time summarized in this review. CONCLUSION: It is clearly suggested from the literature information that the structures and biological activities of Gelsemium have a wide range of attraction from folk to the community of scholars. However, as a highly toxic genus, the work on the detoxification mechanism and toxicology of Gelsemium is urgently needed before entering clinical research. It is noteworthy that the discussion about the relationship between structural and biological activities are a valuable topic of expectation, while the structural modification for active or toxic components may shed light on toxicological breakthrough. Besides the compounds from the plants of genus Gelsemium, the recently reported natural products from its endophytic fungi may provide a supplement for its ethnomedicinal uses and ethnological validity.

Structural Elucidation and Cytotoxic Activity of New Monoterpenoid Indoles from Gelsemium elegans.

Two new monoterpenoid indole alkaloids, gelselegandines F (1) and G (2), were isolated from the aerial parts of Gelsemium elegans. Their structures were elucidated by means of spectroscopic techniques and quantum chemical calculations. The ECD calculations were conducted at the B3LYP/6-311G(d,p) level and NMR calculations were carried out using the Gauge-Including Atomic Orbitals (GIAO) method. Structurally, the two new compounds possessed rare, cage-like, monoterpenoid indole skeletons. All isolated compounds and the total alkaloids extract were tested for cytotoxicity against four different tumor cell lines. The total alkaloids extract of G. elegans exhibited significant antitumor activity with IC50 values ranging from 32.63 to 82.24 ug/mL. In order to discover anticancer leads from the active extraction, both new indole compounds (1-2) were then screened for cytotoxicity. Interestingly, compound 2 showed moderate cytotoxicity against K562 leukemia cells with an IC50 value of 57.02 uM.

Biological Activities and Secondary Metabolites from Sophora tonkinensis and Its Endophytic Fungi.

The roots of Sophora tonkinensis Gagnep., a traditional Chinese medicine, is known as Shan Dou Gen in the Miao ethnopharmacy. A large number of previous studies have suggested the usage of S. tonkinensis in the folk treatment of lung, stomach, and throat diseases, and the roots of S. tonkinensis have been produced as Chinese patent medicines to treat related diseases. Existing phytochemical works reported more than 300 compounds from different parts and the endophytic fungi of S. tonkinensis. Some of the isolated extracts and monomer compounds from S. tonkinensis have been proved to exhibit diverse biological activities, including anti-tumor, anti-inflammatory, antibacterial, antiviral, and so on. The research progress on the phytochemistry and pharmacological activities of S. tonkinensis have been systematically summarized, which may be useful for its further research.

The Beneficial Effects of Combining Anti-Aß Antibody NP106 and Curcumin Analog TML-6 on the Treatment of Alzheimer's Disease in APP/PS1 Mice.

Alzheimer's disease (AD) is a progressive neurodegenerative disease with a multifactorial etiology. A multitarget treatment that modulates multifaceted biological functions might be more effective than a single-target approach. Here, the therapeutic efficacy of combination treatment using anti-Aß antibody NP106 and curcumin analog TML-6 versus monotherapy was investigated in an APP/PS1 mouse model of AD. Our data demonstrate that both combination treatment and monotherapy attenuated brain Aß and improved the nesting behavioral deficit to varying degrees. Importantly, the combination treatment group had the lowest Aß levels, and insoluble forms of Aß were reduced most effectively. The nesting performance of APP/PS1 mice receiving combination treatment was better than that of other APP/PS1 groups. Further findings indicate that enhanced microglial Aß phagocytosis and lower levels of proinflammatory cytokines were concurrent with the aforementioned effects of NP106 in combination with TML-6. Intriguingly, combination treatment also normalized the gut microbiota of APP/PS1 mice to levels resembling the wild-type control. Taken together, combination treatment outperformed NP106 or TML-6 monotherapy in ameliorating Aß pathology and the nesting behavioral deficit in APP/PS1 mice. The superior effect might result from a more potent modulation of microglial function, cerebral inflammation, and the gut microbiota. This innovative treatment paradigm confers a new avenue to develop more efficacious AD treatments.

New Monoterpenoid Indoles with Osteoclast Activities from Gelsemium elegans.

The well-known toxic medicine Gelsemium elegans is widely and historically used to treat bone fracture and skin ulcers by the folk people of China. Two new monoterpenoid indole alkaloids, gelselegandines D and E, together with the known analogue gelegamine A were isolated from G. elegans. Their structures were elucidated by means of spectroscopic techniques and quantum chemical calculations. All isolated compounds were tested for the effects on RANKL-induced osteoclast formation. Interestingly, gelselegandine E and gelegamine A, respectively, showed significant promoting and inhibitory activities on osteoclastogenesis, while gelselegandine D had no activity under the same concentration. This work suggested the different configurations for the carbons near the C-19/20 oxygen rings of the isolated compounds may be the key active groups on osteoclast formation and provided the evidence for the rationality as the traditional treatment for bone-related diseases of G. elegans.