Xuehong Wang

Influence of Hypericum perforatum Extract on Piglet Infected with Porcine Respiratory and Reproductive Syndrome Virus

To study the influence of Hypericum perforatum extract (HPE) on piglets infected with porcine respiratory and reproductive syndrome virus (PRRSV), enzyme-labeled immunosorbent assay (ELISA) and cytopathic effect (CPE) were used to determine in vitro whether HPE could induce swine pulmonary alveolar macrophages (PAMs) to secrete IFN-gamma, and whether PRRSV titers in PAMs were affected by the levels of HPE-induced IFN-gamma. HPE (200 mg kg(-1)) was administrated by oral gavage to piglets infected with the PRRSV in vivo to observe whether HPE affected the viremia, lung viral titers, and weight gain of piglets infected with PRRSV. The results showed that HPE was capable of inducing PAMs to produce IFN-gamma in a dose dependent manner and HPE pretreatment was capable of significantly reducing PRRSV viral titers in PAMs (P<0.01). Administration of HPE to the PRRSV-infected animals significantly (P<0.05) reduced viremia over time as compared with the PRRSV-infected animals. But there was not significant decrease in lung viral titers at day 21 post-infection between the HPE-treated animals and the PRRSV-infected control piglets. There were no significant differences in weight gain over time among the HPE-treatment animals, the normal control, and the HPE control animals. The PRRSV-infected animals caused significant (P<0.01) growth retardation as compared with the HPE controls and the normal piglets. It suggested that HPE might be an effective novel therapeutic approach to diminish the PRRSV-induced disease in swine.

Anti-influenza A virus effect of Hypericum perforatum L. extract

To study the antiviral effect of Hypericum perforatum L. extract (HPE) on influenza A virus (IAV) (H1N1) in vitro and in vivo. Cytopathic effect (CPE) and neutral red (NR) dye uptake were used to examine the antiviral effect of HPE on Madin Darby Canine Kidney (MDCK) cells which were infected with IAV in vitro. HPE was effective against influenza A virus (IAV) in vitro, with a 50% effective concentration (EC50) of 40 μg/mL. The mean 50% cytotoxic concentration (CC50) in the MDCK used in these experiments was 1.5 mg/mL. Ribavirin was run in parallel with EC50 values of 5.0 μg/mL; the mean CC50 for ribavirin was 520 μg/mL. Oral gavage administrations of HPE or ribavirin to mice infected with the IAV were highly effective in preventing death, slowing the decline of arterial oxygen saturation, inhibiting lung consolidation and reducing lung virus titers. The minimum effective dose of HPE in these studies was 31.25 mg/kg/day, which was administered twice daily for 5 d beginning 4 h prior to virus exposure. Below a dosage of 2000 mg/kg/day, almost all treated mice survived, which suggests that HPE is of low toxicity. Ribavirin’s minimum effective dose was 40 mg/kg/day with the LD50 determined to be 200 mg/kg/day. Delay of the initiation of either HPE or ribavirin therapy, using approximately 1/3 LD50 dose each time, could still be protective as late as 48 h after exposure to the IAV. While both agents appeared to have similar efficacy against IAV infections, HPE was considered to be less toxic and may warrant further evaluation as a possible therapy for influenza.

Flavonoids and Phenolics from the Flowers of Limonium aureum

Plants of the Limonium aureum (L.) Hill ex Kuntze (Plumbaginaceae) are rich sources of flavonoids and phenolics [1, 2]. Plants of the Limonium aureum were reported to possess blood invigorating and activating properties and hemostatic and anticancer activity [3]. We studied the flavonoid and phenolic compositions of the flowers of Limonium aureum collected from the north of China, in September 2010 (Gansu region, PRC). Air-dried flowers (1.0 kg) were exhaustively extracted with ethanol. The extract was evaporated to a thick consistency and diluted with 400 mL water. The flavonoids and phenolics were extracted with ethyl acetate and chromatographed over polyamide, silica gel, and Sephadex LH-20 in our continuing chemical examination of this plant. The compounds were isolated from the flowers of Limonium aureum and identified by UV, mass, and NMR spectra and comparison with authentic samples. Eriodictyol, white needle crystals, mp 266–267 C. UV (MeOH, max, nm): 286, 321. 1H NMR and 13C NMR confirmed the identity of the compound as eriodictyol [4]. Luteolin, mp 330–332 C. UV (MeOH, max, nm): 255, 270, and 350. MS (EI): 287 (18), 286 (100), 258 (12), 153 (20), 134 (6), 129 (10), 62 (21), and 44 (47). Authentic samples were used to identify luteolin [5]. Apigenin, mp 346–347 C. UV (MeOH, max, nm): 267, 334. MS (EI): 270 (100), 242 (13), 153 (15), 152 (10), 121 (11), 96 (3), 69 (4) and 43 (7). Authentic samples were used to identify apigenin [6]. 5,7-Dihydroxychromone, white needle crystals, mp 245–247 C. 1H NMR (400 MHz, DMSO-d6, , ppm, J/Hz): 6.07 (1H, d, J = 6, H-6), 6.13 (2H, d, J = 2.0, H-3), 6.24 (2H, d, J = 2.4, H-8), 7.78 (1H, d, J = 6, H-2), 10.30 (1H, s, H-7), 12.50 (1H, s, H-5). 13C NMR (100 MHz, DMSO-d6, , ppm): 93.7 (C-8), 98.9 (C-6), 105.0 (C-10), 110.3 (C-3), 155.6 (C-2), 157.6 (C-4), 161.5 (C-5), 164.0 (C-7), 181.0 (C-4), characterized as 5,7-dihydroxychromone [7]. Quercetin 3-O-D-xyloside, yellow powder, mp 202–204 C. 1H NMR (400 MHz, DMSO-d6, , ppm, J/Hz): 2.95–3.44 (sugar H), 5.35 (1H, d, J = 7.0, H-1 ), 6.19 (1H, br.s, H-6), 6.39 (1H, br.s, H-8), 6.85 (1H, d, J = 8.5, H-5 ), 7.54 (1H, dd, J = 2.0, 8.5, H-6 ), 7.56 (1H, d, J = 2.0, H-2 ). 13C NMR (100 MHz, DMSO-d6, , ppm): 66.0 (C-5 ), 70.3 (C-4 ), 74.6 (C-2 ), 76.9 (C-3 ), 94.1 (C-8), 99.2 (C-6), 102.3 (C-1 ), 104.4 (C-10), 116.3 (C-2 ), 116.6 (C-5 ), 121.0 (C-1 ), 121.9 (C-6 ), 133.2 (C-3), 146.3 (C-3 ), 150.1 (C-4 ), 156.1 (C-2), 156.1 (C-9), 162.6 (C-5), 164.2 (C-7), 177.2 (C-4), characterized as quercetin-3-O-D-xyloside [8]. Myricetin 3-O-D-xylopyranoside, mp 186–187 C. UV spectrum (MeOH, max, nm): 256, 284, 360. 1H NMR (400 MHz, CD3OD, , ppm, J/Hz): 3.50 (1H, dd, J = 3, H-5 ), 3.67 (1H, dd, J = 3, H-4 ), 3.80–3.87 (2H, m, H-2 , 3 ), 5.19 (1H, d, J = 5.8, H-1 ), 6.22 (1H, d, J = 2), 6.41 (1H, d, J = 2), 7.33 (2H, s); acid hydrolysis produced myricetin and xylose, characterized as myricetin 3-O-D-xylopyranoside [9].