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PubMed1984

Inhibition by certain plant extracts of the binding and adenylate cyclase stimulatory effect of bovine thyrotropin in human thyroid membranes.

The present studies were undertaken to explore the mechanism by which, as previous studies have shown, freeze-dried aqueous extracts (FDE) of plants of the species Lycopus virginicus and Lycopus europaeus, Melissa officinalis (Laminaceae), and Lithospermum officinale (Boraginaceae) have the ability to inhibit at least many of the effects of exogenous and endogenous TSH on the thyroid gland. To this end, we have examined the in vitro effects of FDE from these plants on the ability of bovine TSH (bTSH) to both bind to human thyroid plasma membranes (TPM) and activate adenylate cyclase therein. FDE of these four species produced a dose-related, ultimately complete, inhibition of the binding of 125I-labeled bTSH when studied at 4 C in a 20 mM Tris-HCl-0.5% BSA buffer, pH 7.45. Half-maximum inhibition of bTSH binding was produced by approximately 50 mU/ml bTSH and only about 10-30 micrograms/ml of the four active FDE. When studied in Tris-BSA-50 mM NaCl buffer at 37 C, these FDE remained inhibitory to bTSH binding, but their potency was decreased to about one fifth of that seen in the absence of NaCl. The binding of [125I]hCG to rat testis membranes was also inhibited by all of these FDE, but no effect on the binding of [125I]insulin to crude rat liver membranes was observed. In concentrations as high as 1 mg/ml, FDE of Verbena officinalis (Verbenaceae), which belongs to the same order (Tubiflorae) as the other plants, but exhibits no antithyrotropic or antigonadotropic activity in vivo, had no effect on either the binding of bTSH to thyroid membranes or the binding of hCG to rat testis membranes. No inhibition of [125I]bTSH binding occurred when TPM were preincubated with the four active FDE, washed, and then incubated with [125I]bTSH in medium devoid of FDE. Hence, the inhibition of [125I]bTSH binding seen when labeled hormone and active FDE were added together was not due to irreversible binding of FDE to TPM or damage to the TSH receptor. When [125I]bTSH was incubated with the active FDE in Tris-BSA and the mixture was chromatographed on Sephadex G-100 using the same buffer, [125I]bTSH was shifted from an apparent mol wt of 30,000 and eluted at the void volume. Direct binding of [125I]bTSH in fractions from the new, large molecular peak was nil. Addition of a large excess of unlabeled bTSH during preincubation prevented the shift in the elution pattern of [125I] bTSH produced by these FDE.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenylyl Cyclases↗
PubMed1985

Extracts and auto-oxidized constituents of certain plants inhibit the receptor-binding and the biological activity of Graves' immunoglobulins.

Freeze-dried extracts (FDE) of the plants Lycopus virginicus, Lycopus europaeus, Melissa officinalis, and Lithospermum officinale, as well as products of the oxidation of certain of their constituents, have been shown to exert antithyrotropic activity by virtue of their ability to form adducts with TSH that bind weakly, if at all, to the TSH receptor. The thyroid-stimulating immunoglobulin G (IgG) found in the blood of patients with Graves' disease (Graves'-IgG) resemble TSH in their ability to bind to the thyroid plasma membrane, probably at the TSH receptor, and to activate the gland. In view of this similarity, and since some of the aforementioned FDE have been used in the treatment of hyperthyroidism in Graves' disease, we undertook studies of the effect of these FDE and their constituents on the binding and biological action of Graves'-IgG. In all samples of Graves'-IgG tested, incubation with antithyrotropic FDE or their antithyrotropic auto-oxidized constituents decreased their TSH-binding inhibitory activity in a dose-dependent manner. FDE from L. officinale also inhibited in a dose-dependent manner the direct binding to human thyroid membranes of a 125I-labeled preparation of receptor-purified Graves'-IgG. As judged from both stimulation of adenylate cyclase activity in vitro (thyroid-stimulating Ig activity) and enhancement of thyroid iodine release in the McKenzie assay system (LATS activity), antithyrotropic FDE and their auto-oxidized constituents also inhibited the biological responses to Graves'-IgG. FDE and constituents lacking antithyrotropic activity had little or no effect on the TSH-binding inhibitory activity, thyroid-stimulating Ig activity, or LATS activities of Graves'-IgG. Evidence of some degree of specificity of the inhibitory effects of the active compounds on Graves'-IgG was obtained in the demonstration that they failed to inhibit both the direct binding of [125I]insulin to its receptors in human lymphoblastoid IM-9 cells and the ability of IgG preparations containing antiinsulin receptor antibodies to inhibit the binding of labeled insulin. These observations suggest that the active principles in those FDE and their oxidized constituents with antithyrotropic activity may interact with the pathogenically important components of Graves'-IgG to inhibit their ability to bind to the TSH receptor and activate the thyroid, as they do with TSH. Our findings provide a possible rationale for the empirical, though poorly documented, use of FDE in the treatment of Graves' disease and some support for the suggestion that Graves'-specific IgG may have structural similarities to TSH itself.

Adenylyl Cyclases↗
PubMed2003

Immunomodulatory activity of betulinic acid by producing pro-inflammatory cytokines and activation of macrophages.

Betulinic acid (BA), a pentacyclic triterpene isolated from Lycopus lucidus, has been reported to be a selective inducer of apoptosis in various human cancer and shown anti-inflammatory and immunomodulatory properties. We postulated that BA modulates the immunomodulatory properties at least two groups of protein mediators of inflammation, interleukin-1beta (IL-1beta) and the tumor necrosis factor-alpha (TNF-alpha) on the basis of the critical role of the monocytes and tissue macrophages in inflammatory and immune responses. TNF-alpha and IL-1beta were produced by BA in a dose dependent manner at concentration of 0.625 and 10 microg/mL. The production of NO associated with iNOS was inhibited when treated with LPS at the concentration of 2.5 to 20 microg/mL of BA whereas COX-2 expression was decreased at 2.5 to 20 microg/mL. These modulations of inflammatory mediators were examined in LPS-stimulated RAW 264.7 cells and peritoneal macrophages. The morphology of macrophage was also examined and enhanced surface CD 40 molecule was expressed when treated BA at 0.625 to approximately 5 microg/mL with or without LPS. Furthermore, BA (20 microg/mL) enhanced apoptosis by producing DNA ladder in the RAW 264.7 cells. Our results indicated that BA induced activation of macrophage and pro-inflammatory cytokines. This may provide a molecular basis for the ability of BA to mediate macrophage, suppress inflammation, and modulate the immune response.

Adjuvants, Immunologic↗
PubMed2007

Convergence patterns and multiple species interactions in a designed plant mixture of five species.

It is known that convergence and divergence can occur in complex plant communities, but the relative importance of biotic and abiotic factors driving these processes is less clear. We addressed this issue in an experiment using a range of mixed stands of five species that are common in Swiss fens (Carex elata, C. flava, Lycopus europaeus, Lysimachia vulgaris and Mentha aquatica) and two levels of water and nutrients. One hundred and seventy-six experimental mixtures were maintained in large pots (75 l) for two consecutive growing seasons in an experimental garden. The stands varied systematically in the initial relative abundance of each of the five species and in overall initial stand abundance. The changes in biomass over 2 years were modelled as linear functions of treatments and the initial biomass of each species. The dynamics of the system were mainly driven by differences in the identity of species and by a negative feedback mechanism but also by different abiotic conditions. In all mixtures, C. elata became more dominant over time, which caused an overall convergence of community composition. In addition, the rate of change of each species' biomass was negatively related to its own initial abundance. Thus, a negative feedback further contributed to the convergence of communities. Species responded differently to water level and nutrient supply, causing community dynamics to differ among treatments. However, the different abiotic conditions only slightly modified the overall convergence pattern. Competitive interactions between more than two species were weaker than the negative feedback but still significantly influenced the species' final relative abundance. The negative feedback suggests that there is niche partitioning between the species, which permits their coexistence.

Biomass↗
PubMed1996

Automated multiple development thin layer chromatography of some plant extracts.

The separation of ten plant extracts using automated multiple development thin-layer chromatography (AMD -TLC) is described. Alcoholic extracts were obtained from Cinchona succirubra, Aesculus hippocastanum, Berberis vulgaris. Artemisia abrotanum, Carduus marianus, Thuja occidentalis, Baptisia tinctoria, Paulinia cupana, Lycopus europaeus and Echinacea angustifolia. The separation was performed on silica plates (Sil G-50 UV 254 (Macherey-Nagel), 10 x 20 cm). AMD was achieved in 25 steps using methanol, ethyl acetate, toluene, 1,2-dichloroethane, 25% ammonia solution and anhydrous formic acid as modifiers. The chromatograms were evaluated with a Shimadzu CS-9000 dual-wavelength flying-spot scanner. Better separations were obtained using AMD than isocratic elution.

Artemisia↗
PubMed1981

Formation of compounds with antigonadotropic activity from inactive phenolic precursors.

The antigonadotropic activity of Lithospermum and Lycopus species can be attributed to their phenolic components. These compounds represent precursors of biologically active products which are formed by an oxidation step. Complexity and instability of these products aggravates the elucidation of detailed structural properties. Therefore, the type of reaction involved had to be clarified. Among the oxidation products of phenolic substances, the corresponding quinones are found. It can be demonstrated that the reaction between quinones and unoxidized diphenols yields products with strong antigonadotropic activity. This type of reaction - the formation of quinhydrones - is proposed to be engaged in the formation of various products with antigonadotropic activity.

Animals↗
PubMed2000

Inhibition of xanthine oxidase by some Chinese medicinal plants used to treat gout.

The enzyme xanthine oxidase catalyses the oxidation of hypoxanthine to xanthine and then to uric acid, which plays a crucial role in gout. A total of 122 traditional Chinese medicinal plants, selected according to the clinical efficacy and prescription frequency for the treatment of gout and other hyperuricemia-related disorders, have been evaluated for the enzyme inhibitory activity. Among the 122 methanol extracts derived from these species, 69 were shown to be inhibitory at 100 microg/ml, with 29 having greater than 50% inhibition. As to the equal amount of water extracts, 40 were disclosed to be active at 100 microg/ml, with 13 possessing more than 50% inhibition. At 50 microg/ml, 58 methanol and 24 water extracts exhibited inhibitory activity, with 15 of the former and two of the latter showing greater than 50% inhibition. The most active was the methanol extract of the twig of Cinnamomum cassia (Lauraceae) (IC(50), 18 microg/ml), which was followed immediately by those of the flower of Chrysanthemum indicum (Asteraceae) (IC(50), 22 microg/ml) and the leaves of Lycopus europaeus (Lamiatae) (IC(50), 26 microg/ml). Among the water extracts, the strongest inhibition of the enzyme was observed with that of the rhizome of Polygonum cuspidatum (Polygonaceae) (IC(50), 38 microg/ml). The IC(50) value of allopurinol used as a positive control was 1.06 microg/ml. The study demonstrated that the effects for these medicinal plants used for the gout treatment were based, at least in part, on the xanthine oxidase inhibitory action.

Enzyme Inhibitors↗