A new caffeic ester from Incarvillea mairei var. granditlora (Wehrhahn) Grierson

Monoterpene Alkaloids from Incarvillea delavayi Bureau et Franchet and Their Inhibition against LPS Induced NO Production in BV2 Cells

Three new monoterpene alkaloids, delavatines C-E (1-3), along with five known ones (4-8), were separated from the whole plants of Incarvillea delavayi. All compounds were deduced by interpretation of comprehensive NMR spectral data and X-Ray single crystal diffraction, in combination with a quantum chemical calculation of NMR chemical shift coupled with an advanced statistical procedure DP4+. Compounds 1-8 were assessed NO suppressive effect in LPS-stimulated BV2 microglia cells. Compounds 2, 3, 6, and 8 exhibited significant inhibition against NO production in LPS-induced BV2 cells with IC₅₀ values of 25.62, 17.29, 19.94 and 23.88 μM, stronger than or comparable to the positive control (AG) with IC₅₀ value of 26.13 μM.

(+)-2-(1-Hydroxyl-4-oxocyclohexyl) ethyl caffeate suppresses solar UV-induced skin carcinogenesis by targeting PI3K, ERK1/2, and p38

For decades, skin cancer incidence has increased, mainly because of oncogenic signaling pathways activated by solar ultraviolet (UV) irradiation (i.e., sun exposure). Solar UV induces multiple signaling pathways that are critical in the development of skin cancer, and therefore the development of compounds capable of targeting multiple molecules for chemoprevention of skin carcinogenesis is urgently needed. Herein, we examined the chemopreventive effects and the molecular mechanism of (+)-2-(1-hydroxyl-4-oxocyclohexyl) ethyl caffeate (HOEC), isolated from Incarvillea mairei var. grandiflora (Wehrhahn) Grierson. HOEC strongly inhibited neoplastic transformation of JB6 Cl41 cells without toxicity. PI3K, ERK1/2, and p38 kinase activities were suppressed by direct binding with HOEC in vitro. Our in silico docking data showed that HOEC binds at the ATP-binding site of each kinase. The inhibition of solar UV-induced PI3K, ERK1/2, and p38 kinase activities resulted in suppression of their downstream signaling pathways and AP1 and NF-κB transactivation in JB6 cells. Furthermore, topical application of HOEC reduced skin cancer incidence and tumor volume in SKH-1 hairless mice chronically exposed to solar UV. In summary, our results show that HOEC exerts inhibitory effects on multiple kinase targets and their downstream pathways activated by solar UV in vitro and in vivo. These findings suggest that HOEC is a potent chemopreventive compound against skin carcinogenesis caused by solar UV exposure.

Sesquiterpene lactones from the leaves of Hedyosmum brasiliense (Chloranthaceae)

Hedyosmum brasiliense Miq. is an endemic aromatic arborescent shrub that is the only representative of the Chloranthaceae in Brazil. There have been few studies seeking to determine its chemical constituents and/or pharmacological effects. This work describes the isolation and identification of sesquiterpene lactones from the leaves, including guaianolides, elemanolides and a lindenanolide. These were tested against Mycobacterium tuberculosis, together with podoandin, onoseriolide and some other common phenolics. The structures of the isolated compounds were determined based on extensive analysis of 1D and 2D NMR spectroscopic and MS data, as well as comparison with published data. The compounds found were the guaianolides, 1,2-epoxy-10α-hydroxy-podoandin and 1-hydroxy-10,15-methylenepodoandin, the elemenolide 15-acetoxy-isogermafurenolide and the lindenanolide 8α/β,9α-hydroxy-onoseriolide, along with the previously isolated guaianolide podoandin, the lindenanolide onoseriolide and the elemenolide 15-hydroxy-isogermafurenolide. The phenolic compounds isolated were scopoletin, vanillin, vanillic acid, protocatechuic aldehyde and ethyl caffeate. The isolated sesquiterpene lactones did not show anti-mycobacterial activity against isoniazid-sensitive M. tuberculosis cultures at concentrations of 1-30 μM.

Target Identification and Validation of (+)-2-(1-Hydroxyl-4-Oxocyclohexyl) Ethyl Caffeate, an Anti-Inflammatory Natural Product

(+)-2-(1-hydroxyl-4-oxocyclohexyl) ethyl caffeate (HOEC) was isolated from Incarvillea mairei var. granditlora (Wehrhahn) Grierson. The plants of the Incarvillea genus have long been used as folk medicines for the treatment of inflammation-related diseases in China. 5-Lipoxygenase (5-LOX), a key enzyme in the arachidonic acid (AA) cascade, was identified as a potential target of HOEC by a pulldown assay, and then extensively validated by biosensor-based affinity detection, enzyme-based activity assays, cell-based AA metabolite analysis and computer-aided AA network simulation. Further in vivo studies of AA-induced ear oedema, ovalbumin (OVA)-induced lung inflammation and collagen-induced arthritis demonstrated the anti-inflammatory potency and validated the therapeutic target of HOEC. This work revealed that HOEC acted as an anti-inflammatory agent targeting 5-LOX, which not only confirmed the key role of 5-LOX in inflammation but also provided a paradigm for the exploration of natural product mechanisms of action.

Sesquiterpene lactones from Vernonia scorpioides and their in vitro cytotoxicity

Fresh leaves of Vernonia scorpioides are widely used in Brazil to treat a variety of skin disorders. Previous in vivo studies with extracts of this species had also demonstrated a high antitumor potential. This paper reports isolation of four sesquiterpene lactones (hirsutinolides and glaucolides), together with diacetylpiptocarphol, 8-acetyl-13-etoxypiptocarphol, luteolin, apigenin, and ethyl caffeate from fresh leaves and flowers of Vernonia scorpioides. The hypothesis that hirsutinolide 3 is formed during extraction was verified theoretically using Density Functional Theory. The effects of isolated compounds on in vitro tumor cells were investigated, as well as their genotoxicity by means of an in vitro comet assay. The results indicate that glaucolide 2 and hirsutinolide 4 are toxic to HeLa cells. These compounds were genotoxic in vitro, a property that appears to be related to the presence of their epoxy groups, which has been a more reliable indication of toxicity than substitution on C-13 or the presence of alpha,beta-unsaturated keto-groups. These results need to be replicated in vivo in order to ascertain their toxicity.

Cyclohexyl-ethanol derivatives from the roots of Incarvillea mairei

Two new cyclohexyl-ethanol derivatives, incarvmareins A (1) and B (2), together with two known derivatives, 3 and 4, were isolated from the ethanolic extract of the roots of Incarvillea mairei. The structures of the new compounds were elucidated primarily on the basis of analysis of spectroscopic data.