Wei Yuan

Curcumin-free turmeric exhibits anti-inflammatory and anticancer activities: Identification of novel components of turmeric

Turmeric, a dried powder derived from the rhizome of Curcuma longa, has been used for centuries in certain parts of the world and has been linked to numerous biological activities including antioxidant, anti-inflammatory, anticancer, antigrowth, anti-arthritic, anti-atherosclerotic, antidepressant, anti-aging, antidiabetic, antimicrobial, wound healing, and memory-enhancing activities. One component of turmeric is curcumin, which has been extensively studied, as indicated by more than 5600 citations, most of which have appeared within the past decade. Recent research has identified numerous chemical entities from turmeric other than curcumin. It is unclear whether all of the activities ascribed to turmeric are due to curcumin or whether other compounds in turmeric can manifest these activities uniquely, additively, or synergistically with curcumin. However, studies have indicated that turmeric oil, present in turmeric, can enhance the bioavailability of curcumin. Studies over the past decade have indicated that curcumin-free turmeric (CFT) components possess numerous biological activities including anti-inflammatory, anticancer, and antidiabetic activities. Elemene derived from turmeric is approved in China for the treatment of cancer. The current review focuses on the anticancer and anti-inflammatory activities exhibited by CFT and by some individual components of turmeric, including turmerin, turmerone, elemene, furanodiene, curdione, bisacurone, cyclocurcumin, calebin A, and germacrone.

Cytotoxicity and inhibition of DNA topoisomerase I of polyhydroxylated triterpenoids and triterpenoid glycosides

Cytotoxicity and inhibition on human DNA topoisomerase I (TOP1) and II (TOP2) of 74 plant-originated triterpenoids and triterpenoid glycosides were investigated. The cytotoxic compounds are primarily polyhydroxylated oleananes (GI(50) of A549: 1.0-10.19 microM). Sixteen cytotoxic aesculiosides isolated from Aesculus pavia inhibited TOP1 catalytic activity by interacting directly with the free enzyme and preventing the formation of the DNA-TOP1 complex. Interestingly, hydrolysis of six active aesculiosides (1, 4, 6, 8, 10, and 23) lost their TOP1 activities but enhanced their cytotoxicities. None of the test compounds showed any activity against TOP2. Structure-activity relationship (SAR) investigations indicated that cytotoxic oleananes required at least one angeloyl moiety at either C-21 or C-22 but the sugar moiety at C-3 may decrease their cytotoxicities. An angeloyl or tigeloyl group at C-21 is required for oleananes to bind the free TOP1 enzyme although the type and length of acyl moiety at C-22 also affects their activity. However, sugar moiety at C-3 is necessary for their TOP1 activities.

Phenolic compounds and rare polyhydroxylated triterpenoid saponins from Eryngium yuccifolium.

Phytochemical investigation on the whole plant of Eryngium yuccifolium resulted in the isolation and identification of three phenolic compounds (1-3) and 12 polyhydroxylated triterpenoid saponins, named eryngiosides A-L (4-15), together with four known compounds kaempferol-3-O-(2,6-di-O-trans-p-coumaroyl)-beta-D-glucopyranoside (16), caffeic acid (17), 21beta-angeloyloxy-3beta-[beta-D-glucopyranosyl-(1-->2)]-[beta-d-xylopyranosyl-(1-->3)]-beta-D-glucuronopyranosyloxyolean-12-ene-15alpha,16alpha,22alpha,28-tetrol (18), and saniculasaponin III (19). This study reports the isolation of these compounds and their structural elucidation by extensive spectroscopic analyses and chemical degradation.

Phytochemical Constituents and Pharmacological Activities of Eryngium L. (Apiaceae)

Eryngium L. is the largest and arguably the most taxonomically complex genus of the family Apiaceae. The genus has approximately 250 species throughout the world, with the center of diversity in South America. Some Eryngium species are cultivated as ornamental, vegetable, or medicinal crops for folk uses. With increasing chemical and biological investigations, Eryngium has shown its potential as pharmaceutical crops. This review focuses on phytochemistry and pharmacological activities of 127 compounds isolated and identified from 23 species of Eryngium, particularly non- essential oil compounds such as terpenoids, triterpenoid saponins, flavonoids, coumarins, polyacetylenes, and steroids. Eryngium extracts or isolates have shown in vitro bioactivitities such as cytotoxicity against various human tumor cell lines, anti-inflammatory, anti-snake and scorpion venoms, antibacterial, antifungal, and antimalarial, antioxidant, and an- tihyperglycemic effects. In vivo studies through various animal models have also shown promising results. However, chemical constituents and their bioactivities of most species of this highly diversified genus have not been investigated. The molecular mechanism of bioactivities (particularly cytotoxicity and anti-snake and scorpion venoms) of Eryngium isolates remains elusive. Also, anti-tumor activity of polyhydroxylated triterpenoid saponins isolated from Eryngium needed to be furthur explored.

Anthocyanins, Phenolics, and Antioxidant Capacity of Vaccinium L. in Texas, USA

Berries of Vaccinium spp. have long been an important source of food and pharmaceutical ingredients and are considered to have high antioxidant potential. Growing blueberries in Texas, United States is a substantial industry, but there is no report on their antioxidant capacity, total phenolics, and anthocyanins. This study evaluates antioxidant capac- ity and contents of total phenolics and anthocayanins in both fruits and leaves of 19 genotypes including five commercial cultivars and 11 selections of rabbiteye blueberry (V. ashei) and southern highbush (V. corymbosum hybrids), and three native species (V. darrowii, V. arboreum, and V. fuscatum) grown in Nacogdoches, Texas. Significant variations in anti- oxidant capacity (as measured by FRAP) and contents of total phenolics and anthocyanins in fruit were observed among different species, cultivars or selections with less variation observed among individual plants of the same genotype. Our data from rabbiteye blueberry selections and cultivars support the hypothesis that antioxidant capacity is more highly cor- related to total phenolics than anthocyanins. The analysis of five species indicates that antioxidant activity decreased dur- ing ripening but total phenolics contents tended to increase with maturity. Antioxidant capacity, total phenolics, and an- thocyanin content did not change significantly during storage at 4oC or -20oC for two weeks but decreased significantly when berries were oven dried at 65oC for 48 h. Antioxidant capacity and total phenolics content in leaves of each geno- type were 3 to 15 times higher than those in fruits.

Ecdysteroids and a Sucrose Phenylpropanoid Ester from Froelichia floridana

Phytoecdysteroid glycosides (1-5) and a phenylpropanoid ester of sucrose (6) were isolated from the whole plant of Froelichia floridana, along with eight known compounds including three ecdysteroids (7-9), four flavonoids (10-13), and one phenolic compound (14). Structures were determined using a combination of spectroscopic techniques. Compounds 1, 2 and 6-14 were tested in vitro for their activity against human DNA topoisomerase I. Compound 13 (diosmetin) showed marginal inhibition against topoisomerase I with IC(50) of 130 microM in conjunction with low intercalation ability.

Cytotoxic triterpenoid saponins from Aesculus glabra Willd.

Twenty-four acylated polyhydroxyoleanene saponins were isolated from the seeds of Aesculus glabra. Sixteen of them, namely aesculiosides G1-G16 (1-16), were determined as compounds by spectroscopic and chemical analysis. The structural features of all 24 saponins are: (1) arabinofuranosyl units affixed to C-3 of the glucuronopyranosyl unit in the trisaccharide chain; (2) no 24-OH substitution; (3) C-2 sugar moiety substitution of the 3-O-glucuronopyranosyl unit is either glucopyranosyl or galactopyranosyl. The features of these isolated saponin structures provide more evidence for chemical taxonomy within the genus Aesculus. The cytotoxicity of the aesculiosides (1-16) were tested against A549 and PC-3 cancer cell lines with GI₅₀ from 5.4 to >25 μM.

Cytotoxic compounds from invasive giant salvinia (Salvinia molesta) against human tumor cells.

Giant salvinia (Salvinia molesta) is one of the most noxious invasive species in the world. Our bioactivity-guided fractionation of ethanol extract of giant salvinia led to the isolation of 50 compounds. Of the six new compounds (1-6), salviniol (1) is a rare abietane diterpene with a new ferruginol-menthol coupled skeleton and both salviniside I (2) and salviniside II (3) are novel benzofuran glucose conjugates with unique 10-membered macrodiolide structures. Sixteen abietane diterpenes (1, 7-17, and 19-22) demonstrated in vitro activities against human tumor cells, and 7 and 8 showed selective cytotoxicity to tumor cells over normal cells.

Steroids, Alkaloids, and Coumarins from Gelsemium sempervirens

The 95 % ethanol extract of Gelsemium sempervirens showed inhibitory activity against human DNA topoisomerase I (Topo I). Phytochemical investigations of this active extract resulted in the isolation and identification of three new steroids ( 1 - 3), together with eight known compounds 12 beta-hydroxy-5 alpha-pregn-16-ene-3,20-dione ( 4), gelsemine ( 5), sempervirine ( 6), scopoletin ( 7), 7- O- beta- D-glucopyranosylscopoletin ( 8), 7- O- beta- D-apiofuranosyl-(1-->6)- beta- D-glucopyranosylscopoletin ( 9), uvaol ( 10), and 2-(4-hydroxyphenyl)ethyl heptadecanoate ( 11). The structures of the new steroids were determined by extensive NMR and HR-ESI-MS analyses as 21-hydroxy-5 alpha-pregn-16-ene-3,20-dione ( 1), 3-oxoandrosta-16-ene-17-carboxylic acid ( 2), and 3-oxoandrosta-4,16-diene-17-carboxylic acid ( 3). This study suggests that sempervirine ( 6) intercalates to DNA and also inhibits Topo I through modulating the enzyme activity with an IC (50) of 54.5 +/- 15.9 muM.

Cytotoxic triterpenoid saponins from husks of Aesculus californica (Spach) Nutt.

Fifteen polyhydroxyoleanene saponins, aesculiosides C1-C15 (1-15), were isolated from husks of Aesculus californica. Their structures were established by extensive spectroscopic and chemical analyses. The triterpenoid saponins from A. californica have greater structural diversity than those from any other investigated species thus far in the genus Aesculus. The chemotaxonomic characteristic of aesculiosides C1-C15 is that the unit attached to the C-3 of the aglycone is a glucopyranosyl moiety, instead of a glucuronopyranosyl group in the saponins that have been isolated from other Aesculus species. The saponins isolated from A. californica then provide important evolutionary and chemotaxonomic knowledge of the Aesculus genus, a well-known intercontinental disjunct genus in the Northern hemisphere. Aesculiosides C1-C15 (1-15) showed cytotoxicity to human non-small cell lung tumor (A549) with GI50 ranged from 3.76 to >25μM.