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A phytochemical study on the seeds of Cassia obtusifolia was carried out, which finally led to obtain two naphthalenes ( 1 and 2 ), two naphthopyrans ( 3 and 4 ) and twelve anthraquinones ( 5 - 16 ). The structures of all compounds were established mainly by NMR and MS experiments as well as the necessary chemical evidence. Among them, 1 and 2 (obtusinaphthalensides A and B) were identified to be new naphthalene glycosides.

Three previously unreported anthraquinones, fistulaquinones A-C (1-3), together with three known ones (4-6) were isolated from the twigs of Cassia fistula. Their structures were determined by means of extensive NMR and MS spectroscopic analyses. All the isolated compounds were tested for their anti-tobacco mosaic virus (anti-TMV) activity, and compound 3 showed significant activity with inhibition rate of 34.5% at 20 μM concentration, even more potent than positive control. Additionally, compounds 1-6 exhibited moderate cytotoxicity with IC 50 values ranging from 2.8 to 9.4 μM for some tested human tumor cell lines.

Two new flavones, siameflavones A and B (1 and 2), together with five known flavones (3-7) were isolated from the stem of Cassia siamea. Their structures were elucidated by spectroscopic methods including extensive 1D and 2D NMR techniques. Compounds 1-5 were evaluated for their anti-tobacco mosaic virus (Anti-TMV) activity. The results showed that compounds 1-5 showed weak anti-TMV activity with inhibition rates in the range of 11.6-18.5%.

A new naphtho[1,2-b]furan, 2,9-dihydroxy-7-methoxy-4-methylnaphtha[1,2-b]furan-3(2H)-one (1), along with 10 known compounds vanillic acid (2), naringenin (3), glyceryl-1-tetracosanoate (4), moracin J (5), 1,3,8-trihydroxyanthraquinone (6), esculetin (7), mauritianin (8), kaempferol 3-neohesperidoside (9), β-sitosterol (10), and β-daucosterol (11), was isolated from the leaves of Cassia fistula. The structure of the new compound was determined by NMR and X-ray analysis. Compounds 1, 3, 5-9 were isolated from this plant for the first time. The naphtha[1,2-b]furan was firstly isolated from the natural resources.

Three new acetylated anthraquinone glycosides (1-3) were isolated from the seed of Cassia obtusifolia, together with one parent anthraquinone glycoside (1a). Their structures were determined on the basis of spectroscopic methods and physicochemical properties as obtusifoline-2-O-β-d-2, 6-di-O-acetylglucopyranoside (1), obtusifoline-2-O-β-d-glucopyranoside (1a), obtusifoline-2-O-β-d-3, 6-di-O-acetylglucopyranoside (2), and obtusifoline-2-O-β-d-4, 6-di-O-acetylglucopyranoside (3).

The phytochemical investigation of the root bark of Cassia artemisioides (Gaudich. Ex. DC) Randell resulted in the isolation of one new anthraquinone 1,1'-dihydroxy-3,3'-dimethyl-8,8'-dimethoxy-6,6'-O-bianthraquinone (1) along with four known anthraquinones 1,6-dihydroxy-8-methoxy-3-methylanthraquinone (2), 1-hydroxy-8-methoxy-3-methylanthraquinone (3), 1,8-dihydroxy-6-methoxy-3-methylanthraquinone (4), and 1,6,8-trihydroxy-3-methylanthraquinone (5). The structures of the compounds were elucidated using spectroscopic techniques including 1D and 2D NMR. The compounds were evaluated for antioxidant activity. 1,6,8-Trihydroxy-3-methyl anthraquinone (5) showed good activity among the tested compounds.

Cinnamaldehyde (1) is a pharmacologically active ingredient isolated from cassia twig (Ramulus Cinnamomi), which is commonly used in herbal remedies to treat fever-related diseases. Both TRPV1 and TRPM8 ion channel proteins are abundantly expressed in sensory neurons, and are assumed to act as a thermosensor, with the former mediating the feeling of warmth and the latter the feeling of cold in the body. Both of them have recently been reported to be involved in thermoregulation. The purpose of this paper is to further uncover the antipyretic mechanisms of 1 by investigating its effects on the mRNA expression levels and functions of both TRPV1 and TRPM8. The results showed that 1 could up-regulate the mRNA expression levels of TRPV1 at both 37 and 39 degrees C, and its calcium-mediating function was significantly increased at 39 degrees C, all of which could not be blocked by pretreatment of the neuronal cells with ruthenium red, a general transient receptor potential (TRP) blocker, indicating that the action of 1 was achieved through a non-TRPA1 channel pathway. In conclusion, the findings in our in vitro studies might account for part of the peripheral molecular mechanisms for the antipyretic action of 1.

A new chromone named as 5,4'-dihydroxy-7-methyl 3-benzyl chromone (1) along with three known flavonoid compounds as unsubstituted flavone, kaempferol-3-o-rhamnoside and quercetin-3-o-arabinoside have been isolated from the leaves of Cassia nodosa. Their structures have been established by means of chemical and spectral evidences (IR, UV, 1H-NMR, 13C-NMR and mass spectra).