Semisynthesis of Antitrypanosomal p-Quinone Analog Possesing the Komaroviquinone Pharmacophore.

A p-quinone analog having the komaroviquinone pharmacophore fused with a more conformationally flexible cycloheptane ring, was semisynthesized from natural demethlsalvicanol isolated from Perovskia abrotanoides via four steps in 26% overall yield. The IC50 for the antitrypanosomal activity of the analog was 0.55 µM.

Antimalarial alkaloid from Hypoestes forskaolii.

Following on from previous studies, we brought further our quest for anti-malarial agents isolated from plants grown in the Saudi Arabian Peninsula. Methanolic extracts were prepared from eighteen Saudi plants and then tested in vitro to assess their anti-malarial effects on Plasmodium falciparum K1, (a chloroquine-resistant strain) as well as their cytotoxicity on MRC5 (human diploid embryonic lung cell line) cells. Moderate anti-malarial activity was observed in extracts prepared from Hypoestes forskaolii (Vahl) R. Br. (IC50 value of 5.5 µg/ml) and Rhus retinorrhaea (IC50: 7.71 µg/ml). The remaining sixteen plant extracts appeared to be inactive (IC50 > 12.5 µg/ml). A novel phenanthro-quinolizidine alkaloid, 15ß-hydroxycryptopleurine-N-oxide, was isolated from H. forskaolii using bio-guided fractionation procedures. Chloroquine-resistant (K1) and chloroquine-sensitive (FCR3) strains of P. falciparum appeared very sensitive to the anti-malarial activity of 15ß-hydroxycryptopleurine-N-oxide, giving IC50 of 6.11 and 5.13 nM respectively. It showed cytotoxicity against MRC5 "IC50 of 24.45 nM" with selectivity indices of 4.0 and 4.76 against K1 and FCR3 strains, respectively. It is our understanding that this is the first account on phenanthro-quinolizidine alkaloids anti-malarial activity on a chloroquine-resistant P. falciparum strain.

In vivo metabolic profiles of Bu-Zhong-Yi-Qi-Tang, a famous traditional Chinese medicine prescription, in rats by ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry.

Bu-Zhong-Yi-Qi-Tang (BZYQT), a famous traditional Chinese medicine prescription (TCMP), has been extensively used for conditioning sub-health status and diseases caused by spleen-qi deficiency in China for over 700 years. BZYQT is prevalent not only in China, but also in Japan and South Korea for the clinical treatment of chronic diseases, such as fatigue, tuberculosis and loss of appetite after surgery. However, due to a lack of research on the holistic metabolism of BZYQT, the in vivo bioactive components of BZYQT remain unclear, hindering further study of its in vivo mechanism of action and quality control. In the present study, a four-step integrated strategy based on ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UHPLC-Q-TOF/MS) was established to systematically screen the in vivo xenobiotics of BZYQT. Ultimately, a total of 162 xenobiotics (59 prototypes and 103 metabolites) were identified or tentatively characterized, including 48 in plasma, 147 in urine and 58 in feces, while the in vivo metabolic profile of atractylenolide III (a major component of BZYQT) was elucidated for the first time. The xenobiotics of BZYQT mainly included flavonoids from Astragali Radix, Glycyrrhizae Radix et Rhizoma and Citrus reticulatae Pericarpium; lactones from Angelicae Sinensis Radix and Atractylodis Macrocephalae Rhizoma; and triterpenoid saponins from Cimicifugae Rhizoma. After oral administration, BZYQT-related components underwent diverse metabolic pathways. Among them, flavonoids mainly underwent glucuronidation, sulfation and demethylation, while lactones mainly underwent hydroxylation and acetylcysteine conjugation, and deglycosylation was the major metabolic reaction of saponins. Our investigation gives a comprehensive analysis of the metabolic characteristics of BZYQT and will provide an important basis for further studying the pharmacokinetics of BZYQT to explore its in vivo disposal features and discover its in vivo bioactive components.

Plant-derived alkaloid sinomenine potentiates glucocorticoid pharmacodynamics in mitogen-activated human peripheral blood mononuclear cells by regulating the translocation of glucocorticoid receptor.

Sinomenine has been used as an antirheumatic drug in China. Glucocorticoid combined with sinomenine could be an alternative therapeutic approach. In this study, we evaluated the sinomenine potential effect on glucocorticoid pharmacodynamics in vitro using a human peripheral blood mononuclear cell (PBMC) culture system. We also disclosed the possible action mechanism of sinomenine with a focus on P-glycoprotein function and glucocorticoid receptor (GR) translocation into nucleus. The median (range) of methylprednisolone IC50 values against the PBMC proliferation was 3.18 (0.45-6.81) ng/mL, whereas the median (range) IC50 values of methylprednisolone combined with 0.03, 0.3, 3, and 30 µM sinomenine were 1.85 (0.05-5.15), 0.83 (0.10-3.90), 0.56(0.09-1.62), and 0.59(0.05-1.30) ng/mL, respectively. Sinomenine significantly decreased the IC50 values of methylprednisolone and enhanced the immunosuppressive effect of methylprednisolone (p < 0.05). Sinomenine alone regulated the GR translocation in both Jurkat T cells and normal human PBMCs, and the combination of sinomenine and methylprednisolone showed stronger GR-modulatory activity than methylprednisolone alone. Thus, the additive effect of sinomenine to promote the methylprednisolone immunosuppressive efficacy was suggested to be related to nuclear GR-translocation. However, sinomenine did not significantly inhibit the P-glycoprotein function in the activated PBMCs, suggesting that sinomenine's additive effect seemed to be unrelated with the P-glycoprotein inhibition.

Mucosal immunomodulatory evaluation and chemical profile elucidation of a classical traditional Chinese formula, Bu-Zhong-Yi-Qi-Tang.

ETHNOPHARMACOLOGICAL EVIDENCE: With fast development and high pace life in modern society, autoimmune diseases like inflammatory bowel disease had become increasingly common. Bu-Zhong-Yi-Qi-Tang (BZYQT), a famous traditional Chinese medicine prescription (TCMP), has been used for 700 years mainly in Eastern Asia countries for the treatment of gastrointestinal and respiratory disorder, and weakness after serious diseases. These diseases were proved to be closely related to human immune system, among which, mucosal immune system is the largest immune system. So it is necessary to discover the mucosal immune related bioactive components of BZYQT. AIM OF THE STUDY: To evaluate the mucosal immunomodulatory bioactivity of BZYQT and ingredients. MATERIALS AND METHODS: Peyer's patches were collected from mice administrated orally with BZYQT, its related Octadecylsilane (ODS) fractions and polysaccharide part. Productions of several cytokines including IL-2, IL-4, IL-5, and IFN-γ from T lymphocytes were tested with enzyme linked immunosorbent assay (ELISA) by Peyer's patch cells ex vivo experiments. Chemical profile including low molecular part and polysaccharide part were investigated. Low molecular part of BZYQT and related ODS fractions were analyzed by ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC-Q/TOF-MS) based on LC-MS information from self-established compound library. exclusion chromatography, and chemical property has been analyzed. RESULT: Three-days' administration of BZYQT enhanced productions of IL-4 and IFN-γ in T lymphocytes of Peyer's patches in addition to IL-2. Some hydrophobic low molecular weight fractions (30%, 70% and 100% MeOH ODS fraction), which were fractionated from BZYQT by ODS column chromatography, showed enhancing or suppressive effects on productions of IL-2, IL-4 or IL-5 in T lymphocytes of Peyer's patches after oral administration. Besides, 161 components from hydrophobic low molecular weight fractions of BZYQT were unequivocally identified or tentatively characterized by UPLC-Q/TOF-MS according to retention time behaviors and fragments, and most of them were flavonoids and saponins from Glycyrrhizae Radix, Citri Reticulatae Pericarpium, and Cimicifugae Rhizoma. Polysaccharide part was separated and purified both by anion-exchange and size. BZYQT also contained at least one neutral and three weakly or strongly acidic polysaccharides, and analysis of their chemical properties indicated that a neutral polysaccharide was glucan, and acidic polysaccharides possessed heteroglycan and pectic arabinogalactan features. Murine administration of polysaccharide fractions of BZYQT induced different changes on functions of T lymphocytes in Peyer's patches from hydrophobic low molecular weight fractions. By experiment using intranasally-immunized mice, BZYQT negatively regulated antibody response in lung as combinatorial actions of its low molecular weight ingredients and polysaccharides. CONCLUSION: BZYQT contains several low and macromolecular weight ingredients, which affect to immune-function of T lymphocytes in Peyer's patches, and the formula expresses its regulative activity on lower respiratory immune system through combinatorial actions of these ingredients on immunocompetent cells in Peyer's patches.

Peyer's patch-immunomodulating glucans from sugar cane enhance protective immunity through stimulation of the hemopoietic system.

The aim of the present study was chemical clarification of in vitro Peyer's patch-immunomodulating polysaccharides in sugar cane molasses, and evaluation of in vivo modulating activity on immune function of T lymphocytes in Peyer's patches and on microenvironment of hemopoietic system. Five kinds of glucans, comprising of dextranase-sensitive and activity-related d-glucosyl moieties, were purified as in vitro Peyer's patch-immunomodulating polysaccharides from the molasses. Oral administration of a glucan-enriched subfraction induced IL-2 and GM-CSF-producing T lymphocytes in Peyer's patches, resulting in enhancement of IL-6 production in a hemopoietic microenvironment to boost neutrophil numbers in the peripheral blood stream. Oral administration of purified glucan or glucan-enrich sub-fraction of sugar cane reduced the number of Plasmodium berghei- or P. yoelii-infected erythrocytes in a murine infection model, using polysaccharide alone or via co-administration with the antimalarial drug, artesunate. These results suggested that Peyer's patch-immunomodulating glucans enhanced protective immunity through axis of Peyer's patches-hemopoietic system.

The common lavender (Lavandula angustifolia Mill.) pectic polysaccharides modulate phagocytic leukocytes and intestinal Peyer's patch cells.

Two pectic (chPS-L1, chPS-L2) and one polyphenolic (chPP-L) fractions were obtained from lavender flowers after boiling water extraction, exhaustive removing of alcohol-soluble molecules and SEC. chPS-L1 (52.4kDa) contains mainly low-acetylated and high-methoxylated homogalacturonans (HG), and smaller rhamnogalacturonan (RG) I backbone fragments rich in 1,3,5-branched arabinan and arabinogalactan (AG) II side chains. chPS-L2 (21.8kDa) contains predominantly similarly esterified HG, followed by RGI with AGII structures and RGII. The prevalence of catechin and epicatechin in chPP-L indicates that they form weak interactions with pectins. chPS-L1 and chPS-L2 enhanced ß2-integrin expression on neutrophils, inducing ROS generation and macrophage NO production. Both the effects on ß2-integrin and high complement fixation activity of chPS-L1 were proposed for its inhibitory action against PMA- and OZP-activated ROS formation. This, together with suppression of NO generation after co-stimulation with chPS-L1 and LPS, suggested anti-inflammatory activity of studied pectins. Lavender polysaccharides expressed intestinal Peyer's patch immunomodulating activity.

Acidic polysaccharide complexes from purslane, silver linden and lavender stimulate Peyer's patch immune cells through innate and adaptive mechanisms.

Three polysaccharide complexes (PSCs) were isolated from the aerial parts of common purslane (Portulaca oleracea L.), and the flowers of common lavender (Lavandula angustifolia Mill.) and silver linden (Tilia tomentosa Moench) by boiling water extraction and ethanol precipitation. The chemical composition and immunomodulating effects of isolated PSCs were characterized. The chemical characterization revealed that the three samples contain mainly pectic polysaccharides. They exhibited ex vivo intestinal immunomodulating activity through the murine Peyer's patch-mediated bone marrow cell proliferation test at 100µg/ml concentration. At the same time, they stimulated ex vivo human blood T-cell populations (CD4+/CD25+ and CD8+/CD25+), phagocytic leukocytes (CD14+ and CD64+ cells) and induced IL-6 production from human white blood cells and Peyer's patch cells. The herbal PSCs stimulated ex vivo ROS production from whole blood phagocytes and showed unspecific in vitro anti-proliferative activity against normal and A549, HeLa and LS180 tumor cells. This is the first report on immunomodulating studies of linden flower pectins and chemical and biological activity characterization of lavender polysaccharides. Our study demonstrates that similarly to purslane, lavender and silver linden herbal materials contain immunomodulating polysaccharides that could be useful for support of compromised immune system.

Herquline A, produced by Penicillium herquei FKI-7215, exhibits anti-influenza virus properties.

In the course of screening for new anti-influenza virus antibiotics, we isolated herquline A from a culture broth of the fungus, Penicillium herquei FKI-7215. Herquline A inhibited replication of influenza virus A/PR/8/34 strain in a dose-dependent manner without exhibiting cytotoxicity against several human cell lines. It did not inhibit the viral neuraminidase.

Alleviative Effects of a Kampo (a Japanese Herbal) Medicine "Maoto (Ma-Huang-Tang)" on the Early Phase of Influenza Virus Infection and Its Possible Mode of Action.

A Kampo medicine, maoto, has been prescribed in an early phase of influenza-like illness and used for a treatment of influenza clinically in Japan these days. However, the efficacy of maoto against the virus infection remains to be elucidated. This study was conducted to evaluate the alleviative effects of maoto against early phase of influenza virus infection and its preliminary mode of actions through immune systems. When maoto (0.9 and 1.6 g/kg/day) was orally administered to A/J mice on upper respiratory tract infection of influenza virus A/PR/8/34 from 4 hours to 52 hours postinfection (p.i.) significant antipyretic effect was shown in comparison with water-treated control. Administration of maoto (0.8 and 1.3 g/kg/day) significantly decreased the virus titers in both nasal (NLF) and bronchoalveolar lavage fluids (BALF) at 52 hours p.i., and significantly increased the anti-influenza virus IgM, IgA, and IgG1 antibody titers in NLF, BALF, and serum, respectively. Maoto also increased significantly the influenza virus-bound IgG1 and IgM antibody titers in serum and the virus-bound IgM antibody titer in even the BALF of uninfected A/J mice. These results indicate that maoto exerts antipyretic activity in influenza virus-infected mice and virus reducing effect at an early phase of the infection through probably augmentation of the virus-bound natural antibodies.

Semisynthesis of salviandulin E analogues and their antitrypanosomal activity.

A series of analogues of salviandulin E, a rearranged neoclerodane diterpene originally isolated from Salvia leucantha (Lamiaceae), were prepared and their in vitro activity against Trypanosoma brucei brucei was evaluated with currently used therapeutic drugs as positive controls. One of the 19 compounds prepared and assayed in the present study, butanoyl 3,4-dihydrosalviandulin E analogue was found to be a possible candidate for an antitrypanosomal drug with fairly strong antitrypanosomal activity and lower cytotoxicity.

Intestinal Peyer's patch-immunomodulating glucomannans from rhizomes of Anemarrhena asphodeloides Bunge.

During screening for intestinal Peyer's patch-immunomodulating polysaccharides from plant resources including medicinal herbs, a potent modulating activity was observed in a crude polysaccharide fraction (AS-1) from the rhizome of Anemarrhena asphodeloides Bunge. Oral administration of AS-1 (100 mg/kg/day) to aged BALB/c mice enhanced productions of IL-10, IFN-γ and IL-6 from Peyer's patch immunocompetent cells, and its oral administration to ovalbumin (OVA)-fed B10.A mice led to significant suppression on induction of OVA-specific IgE in systemic immune system. Further fractionation of the polysaccharides in the crude polysaccharide fraction, AS-1, yielded 4 polysaccharide fractions that were potently active, and contained glucomannans. Treatment of these polysaccharide fractions with endo-ß-D-(1→4)-mannanase significantly decreased their activities. Mannanase digestion of the active glucomannan gave both long and short hexosyl-oligosaccharides, whereas konjac glucomannan, which was inactive, released short oligosaccharides. Structural analysis indicates that the long oligosaccharides from the active glucomannan contain mannanase-resistant complex structure comprising ß-D-Man and ß-D-Glc.

Immunomodulating pectic polysaccharides from waste rose petals of Rosa damascena Mill.

A water-soluble polysaccharide (RP-1) was obtained from distilled rose petals of Rosa damascena Mill. as an attempt for valorization of the waste. RP-1 showed in vitro intestinal immune system modulating activity through Peyer's patch cells and IL-6 producing activity from macrophages. RP-1 lost most of its immunomodulating activity by degradation of the carbohydrate moiety with periodate. RP-1 was fractionated by anion-exchange and gel filtration chromatography and some of the fractions showed significant intestinal immune system modulating activity. The active fractions were suggested to be pectic polysaccharides and type II arabino-3,6-galactan from the component sugar analyses and the reactivity with Yariv antigen. When some active fractions were digested with endo α-d-(1→4)-polygalacturonase, highest molecular weight fragments which were considered as rhamnogalacturonan I, showed potent immunomodulating activities. To our knowledge, this is a first report which explores the possibility for utilization of waste rose petals as a source of immunomodulating pectic polysaccharides.

Modulation of chemokine expression on intestinal epithelial cells by Kampo (traditional Japanese herbal) medicine, Hochuekkito, and its active ingredients.

The intestinal epithelial cells sit at the interface between a lumen and a lamina propria or lymph nodes such as Peyer's patches, where they play important roles in maintaining intestinal homeostasis through chemokine secretion. This study investigated the effect of Hochuekkito (TJ-41)-a traditional Japanese herbal (Kampo) formula used as a tonic for weakness-on chemokine expression in intestinal epithelial cells in order to explore the mechanism of its modulating effect against mucosal immunity. When cells from the rat normal small intestinal epithelial cell-line IEC-6 were stimulated with TJ-41, mRNA expression of CC chemokine ligand (CCL) 11 (eotaxin), CCL20 (MIP-3α) and CCL25 (TECK) was enhanced. Oral administration of TJ-41 to methotrexate-treated mice enhanced mRNA expression of CCL25 and keratinocyte growth factor in the jejunum with, decreasing mRNA expression of the inflammatory marker tumor necrosis factor (TNF)-α. Although oral administration of TJ-41 did not affect CCL20 mRNA expression in villus epithelium of methotrexate-treated mice, enhancement of CCL20 mRNA expression was observed in Peyer's patches. Immunohistochemical analysis detected dense staining with anti-CCL20 antibody in the follicle-associated epithelium region of Peyer's patches in mice administered TJ-41. Analysis of active ingredients indicates that polysaccharide-containing macromolecules in TJ-41 contribute to the enhancement of CCL20 mRNA expression through an intracellular signal cascade via nuclear factor kappa B (NF-κB) activation.

Involvement of neuropeptide Y signaling in the antidepressant-like effect and hippocampal cell proliferation induced by kososan, a Kampo medicine, in the stress-induced depression-like model mice.

Neuropeptide Y (NPY) and Orexin-A (OX-A), well-known neuropeptides associated with feeding and arousal, show antidepressant-like properties via hippocampal cell proliferation. Previous studies have revealed that kososan, a Kampo (Japanese herbal) medicine, has an antidepressant-like effect in behavioral animal models of depression; the mechanisms underlying this effect may involve the orexinergic system and subsequent upregulation of hippocampal cell proliferation. However, the roles of NPY in kososan's antidepressant-like effect remain unclear. Here we investigated whether the regulation of the NPY system could play crucial roles in this effect in the stress-induced depression-like model mice. The antidepressant-like effect of kososan administered orally (1.0 g/kg) for 28 d was abolished by a continuous intracerebroventricular injection of BIBO3304, a neuropeptide Y1 receptor antagonist, for 7 d. Likewise, BIBO3304 injection blocked the kososan-induced increases in hippocampal cell proliferation and cluster formation of neural progenitor cells. On the other hand, BIBO3304 injection did not affect kososan-induced increases in hypothalamic OX-A-producing cells or in serum OX-A levels. These results suggest that the control of the NPY system in the brain plays an essential role in kososan's antidepressant-like effect and facilitates hippocampal cell proliferation, both of which could be attributed, at least in part, to the control of the NPY system subsequent to the control of the OX-A system.

In vitro antitrypanosomal activity of bis(bibenzyls)s and bibenzyls from liverworts against Trypanosoma brucei.

During the course of our screening program to discover new antitrypanosomal compounds, 17 known plant aromatic compounds [12 bis(bibenzyls)s and 5 bibenzyls] were evaluated for in vitro activity against Trypanosoma brucei brucei. Sixteen compounds were found to exhibit antitrypanosomal activity. In particular, three compounds, marchantin A (1), plagiochin A (5) and 2(R)-2-isopropenyl-6,7-dihydroxy-4-(2-phenylethyl)dihydrobenzofuran (16) demonstrated moderate selective and potent antitrypanosomal activities in vitro. We detail here the antitrypanosomal properties and cytotoxicities of the compounds in comparison with two commonly used therapeutic drugs, eflornithine and suramin. Our finding represents the first report of the promising trypanocidal activity of these compounds. The research also provides valuable insight into structure-activity relationships and the possible mode of action of the compounds.

In vivo anti-influenza virus activity of Japanese herbal (kampo) medicine, "shahakusan," and its possible mode of action.

Background. A Kampo medicine, Shahakusan (SHS), has been prescribed in late phase of infection that causes inflammations in the lung. But effect of SHS on viral infection in respiratory tract has never been reported. Objectives. To evaluate anti-influenza virus activity of SHS and its mode of actions through immune systems. Methods. SHS (0.3 g/kg/day) was orally administered to BALB/c miceforupper (URI) or lower respiratory tract infection (LRI) of influenza virus A/PR/8/34. The virus titer of nasal lavage fluid (NLF) at 5 or 2 day postinfection (p.i.) and cytokine mRNA expressions in mandibular lymph node or lung at 5 or 4 day p.i. were evaluated for URI or LRI, respectively. The histopathological examinations of lung tissue and NK cell activity in the splenocytes were also evaluated at 4 day p.i. on LRI. Results. When SHS was administered from 7 days before to 4 days p.i. for URI, the virus titer was significantly decreased in comparison with water-treated control, and IL-4, IL-1ß, and IL-10 mRNA expression was decreased, but IL-12A mRNA expression was increased. Administration of SHS from one day before to one day p.i. for LRI significantly decreased the virus titer. SHS also decreased infiltration of inflammatory cells in the bronchoalveolar spaces and damage of desquamated mucosal epithelia of bronchiole, decreased IP-10 mRNA expression, and increased NK cell activity. Conclusion. SHS has no direct effect on influenza virus infection but exerts antiviral effect in mice by its immunomodulating activity through action of NK cells and anti-inflammatory activity in the lung.

In vitro antitrypanosomal activity of some phenolic compounds from propolis and lactones from Fijian Kawa (Piper methysticum).

During our search to discover new antitrypanosomal compounds, eight known plant compounds (three phenolic compounds and five kawa lactones) were evaluated for in vitro activity against Trypanosoma brucei brucei. Among them, we found two phenolic compounds and three kawa lactones possessing an α-pyrone influenced antitrypanosomal property. In particular, ß-phenethyl caffeate, farnesyl caffeate and dihydrokawain exhibited high or moderate selective and potent antitrypanosomal activity in vitro. We detail here the antitrypanosomal activity and cytotoxicities of the compounds, in comparison with two commonly used antitrypanosomal drugs (eflornithine and suramin). Our findings represent the first report of the promising trypanocidal activity of these compounds.

In vitro anti-influenza virus activity of a cardiotonic glycoside from Adenium obesum (Forssk.).

Methanolic extracts of six Saudi plants were screened for their in vitro antiviral activity using influenza virus A/PR/8/34 (H1N1) and MDCK cells in an MTT assay. The results indicated that the extracts of Adeniumobesum and Tephorosianubica possessed antiviral activity (99.3 and 93.3% inhibition at the concentration of 10 µg/ml, respectively). Based on these results A. obesum was selected for further study by applying bioactivity-guided fractionation to isolate its antiviral principle. The antiviral principle was isolated from the chloroform fraction through solvent fractionation, combined open liquid chromatography and HPLC. The isolated active compound A was identified as oleandrigenin-ß-D-glucosyl (1→4)-ß-D-digitalose, on the basis of its spectral analysis (MS, 1D and 2D NMR). The isolated glycoside showed reduction of virus titre by 69.3% inhibition at concentration of 1 µg/ml (IC(50)=0.86 µg/ml).

Patchouli alcohol: in vitro direct anti-influenza virus sesquiterpene in Pogostemon cablin Benth.

During the screening of anti-influenza virus substances from traditional herbal medicines, the methanol extract from the leaves of Pogostemon cablin Benth. showed potent in vitro antiviral activity (99.8% inhibition at a concentration of 10 µg/mL) against influenza virus A/PR/8/34 (H1N1). The anti-influenza virus principle was isolated from the hexane-soluble fraction, through solvent fractionation, repeated silica gel column chromatography, and reversed-phase HPLC. The major active principle was a volatile substance that was identified as a sesquiterpene, patchouli alcohol (1), on the basis of its spectral analyses. When anti-influenza virus activity against A/PR/8/34 was evaluated by the plaque forming assay, patchouli alcohol reduced the number of plaques by 75% at 2 µg/mL and 89% at 10 µg/mL. Patchouli alcohol showed dose-dependent anti-influenza virus activity, and its IC(50) value was estimated to be 2.635 µM. Although 11 different sesquiterpenes were tested for antiviral activity against influenza virus A/PR/8/34, no or negligible activity was observed except for patchouli alcohol. Patchouli alcohol did not show anti-influenza virus activity against A/Guizhou/54/89 (H3N2), but showed weak activity against B/Ibaraki/2/85 (IC(50) = 40.82 µM). Patchouli alcohol did not show inhibitory activity against influenza virus neuraminidase.