This study aims at investigating the estrogenic activity and active cucurbitane-type triterpenoid compounds of bitter gourd (Momordica charantia, MC) using a transactivation assay for estrogen receptors (ER) α and β. The lyophilized fruits of MC were exhaustively extracted with ethyl acetate (EA) and 95% ethanol (EtOH), sequentially. The nonsaponifiable fraction (NS) of the EA extract as well as the acid hydrolyzed EtOH extract (AH) was fractionated and isolated by repeated column chromatography and further purified by preparative HPLC or RP-HPLC. One known compound, 5β,19-epoxycucurbita-6,24-diene-3β,23ξ-diol (6), was isolated from the NS, and five new compounds (1-5) were isolated from AH and identified as cucurbita-6,22(E),24-trien-3β-ol-19,5β-olide (1), 5β,19-epoxycucurbita-6,22(E),24-triene-3β,19-diol (2), 3β-hydroxycucurbita-5(10),6,22(E),24-tetraen-19-al (3), 19-dimethoxycucurbita-5(10),6,22(E),24-tetraen-3β-ol (4), and 19-nor-cucurbita-5(10),6,8,22(E),24-pentaen-3β-ol (5). In the noncytotoxic concentration range, compounds 1, 2, 5 and 6 showed weak agonistic activity via ER α and β. Compounds 1, 2, 3 and 6 significantly antagonized the transactvation of 17β-estradiol (E(2)) via both ER α and β. In conclusion, this study demonstrates, for the first time as far as we know, the partial agonist/antagonist activity via ER of four new and one known cucurbitane-type triterpenoids from MC. Further studies are worthy to explore the selective estrogen receptor modulator (SERM) activity of MC.

Chamaecyparis obtusa Sieb. and Zucc. var. formosana (Hayata) Rehder is the dominant species in the temperate forest of Yuanyang Lake Nature Reserve (YYL), Taiwan. Although downed logs of C. obstusa var. formosana occupy only a small percentage of the forest floor area in YYL, they are important regeneration substrates. Seedlings of this species often grow without competition on the new downed logs, and a few broadleaf trees grow with them. We hypothesized that the bark of the newly fallen logs possesses allelopathic potential that provides a habitat especially suitable for seedling establishment. Eight different seeds including those from Lactuca sativa L. (lettuce), Bidens pilosa (an invasive weed), and six species in YYL were planted on the bark of the downed logs in an incubator for germination tests. Two dominant species in the forest of YYL, C. obtusa var. formosana and Rhododendron formosanum, were able to grow normally, but the others, Pieris taiwanensis, Barthea formosana, Chamaecyparis formosensis, Miscanthus transmorrisonensis, lettuce, and B. pilosa were growth inhibited. A bioactivity-guided isolation was designed to isolate allelochemicals from the bark. Salicylic acid, one of the inhibiting substances, was isolated and identified by gas chromatography/mass spectroscopy (GC/MS), proton nuclear magnetic resonance ((1)H NMR), and infrared (IR). Bioassay of salicylic acid confirmed a phytotoxic effect. The results suggest that the dominance of C. obtusa var. formosana seedlings on bark could be partly due to allelopathy.

Calocedimers A, B, C, and D, together with four known compounds, platydiol, alpha-cadinol, ferrugiol, and 6,7-dehydroferrugiol, were isolated from the bark of Calocedrus macrolepis var. formosana. Calocedimers A, B, C, and D are the dimers of abietane-O-camphane, abietane-O-cadinane, abietane-O-abietane, and abietane-O-abietane, respectively. Their structures were elucidated from spectroscopic data.

Leucine-rich repeat (LRR) proteins are advocated for being assessed in vaccine development. Leptospiral LRR proteins were identified recently in silico from the genome of Leptospira borgpetersenii serogroup Sejroe, the seroprevalence of leptospiral infections of cattle in Thailand. Two LRR recombinant proteins, rKU_Sej_LRR_2012M (2012) and rhKU_Sej_LRR_2271 (2271), containing predicted immunogenic epitopes, were investigated for their cross-protective efficacies in an acute leptospirosis model with heterologous Leptospira serovar Pomona, though, strains from serogroup Sejroe are host-adapted to bovine, leading to chronic disease. Since serovar Pomona is frequently reported as seropositive in cattle, buffaloes, pigs, and dogs in Thailand and causes acute and severe leptospirosis in cattle by incidental infection, the serogroup Sejroe LRR proteins were evaluated for their cross-protective immunity. The protective efficacies were 37.5%, 50.0%, and 75.0% based on the survival rate for the control, 2012, and 2271 groups, respectively. Sera from 2012-immunized hamsters showed weak bactericidal action compared to sera from 2271-immunized hamsters (p < 0.05). Therefore, bacterial tissue clearances, inflammatory responses, and humoral and cell-mediated immune (HMI and CMI) responses were evaluated only in 2271-immunized hamsters challenged with virulent L. interrogans serovar Pomona. The 2271 protein induced prompt humoral immune responses (p < 0.05) and leptospiral tissue clearance, reducing tissue inflammation in immunized hamsters. In addition, protein 2271 and its immunogenic peptides stimulated splenocyte lymphoproliferation and stimulated both HMI and CMI responses by activating Th1 and Th2 cytokine gene expression in vaccinated hamsters. Our data suggest that the immunogenic potential renders rhKU_Sej_LRR_2271 protein a promising candidate for the development of a novel cross-protective vaccine against animal leptospirosis.