Antinociceptive activity of Ligusticum porteri preparations and compounds.

CONTEXT: The roots and rhizomes of Ligusticum porteri Coulter & Rose (Apiaceae) are widely used in Mexican folk medicine for several purposes, including painful complaints. OBJECTIVE: The main goal of this work was to demonstrate the analgesic action in mice of some preparations and major compounds from L. porteri. MATERIALS AND METHODS: The extracts, aqueous (AE) and organic (OE), the essential oil (EO) and major compounds (10-316 mg/kg) from L. porteri were evaluated as potential antinociceptive agents using the acetic acid-induced writhing and hot plate tests in ICR mice. RESULTS: All preparations tested exhibited significant antinociceptive effect in the two animal pain models selected. AE and EO were more effective in the writhing test while OE had a better effect in the hot-plate model. On the other hand, Z-ligustilide (1) provoked an increment in the latency period to the thermal stimuli in the hot-plate test at a dose of 31.6 mg/kg, and a decrease in the number of abdominal writhes at 10 mg/kg. Z-3-butylidenephthalide (2) induced a dose-dependent antinociceptive action in the hot-plate assay; this compound was also effective for controlling the pain provoked by chemical irritation at the doses of 10 and 31.6 mg/kg. Finally, diligustilide (3) inhibited the number of writhing responses at all doses tested but was inactive in the hot-plate model. CONCLUSION: The present investigation provides in vivo evidence supporting the use of L. porteri to treat painful conditions in folk medicine.

Neuroprotective evaluation of Tilia americana and Annona diversifolia in the neuronal damage induced by intestinal ischemia.

Tilia americana and Annona diversifolia are plants widely distributed in Mexico and sold in markets for their medicinal properties on the central nervous system (CNS) including possible neuroprotection. Pharmacological studies have corroborated CNS activities due to flavonoid constituents, but evidence of their neuroprotector effects are lacking. This study was conducted to test aqueous and organic extracts of these two plants for neuroprotective effects in a novel experimental model of intestinal ischemia in situ. T. americana and A. diversifolia aqueous and organic extracts were administrated to guinea pigs at an oral dose of 100 and 300 mg/kg for 15 days. Twenty four hours after the last administration, the animals were anesthetized and intestinal ischemia in situ was induced by clamping for 80 min selected branches of the superior mesenteric artery. Ischemic segments placed in an in vitro organ bath were stimulated electrically (0.3 Hz frequency, 3.0 ms duration, 14 V intensity) and chemically (ACh; 1 × 10(-9) to 1×10(-5) M). Neuroprotection was considered present when the depressed contractile response of the ischemic tissue to electrical stimulation was normalized in the treated animals. Results showed that pretreatment with the T. americana hexane and aqueous extracts, but not with those from A. diversifolia, significantly improved responses of the ischemic tissue. These results suggest that T. americana possesses neuroprotective effects against neuronal damage induced by ischemia, and that flavonoids as well as non-polar constituents are involved. Our study supports the use of this plant in folk medicine and suggests its possible effectiveness for stroke prevention.

Gastrointestinal activity of Justicia spicigera Schltdl. in experimental models.

Justicia spicigera Schltdl. (Acanthaceae) is used for treatment of gastrointestinal illnesses therapy in traditional medicine. The objective of this study was to give evidence of the antinociceptive and spasmolytic effects of the J. spicigera ethanol extract (JS EtOH) using in in vivo and/or in vitro assays. The JS EtOH exerted regulatory effect on the motility and a partial relaxing response on the intestinal tissue. Furthermore, a significant abdominal antinociceptive response was obtained in mice, which was totally abolished in the presence of 5-HT1A receptor antagonist (WAY100635, 0.1 mg/kg, s.c.) and partially by blocking opioid receptors (NX, 1 mg/kg, i.p.), whereas the inhibition of the NO synthesis (L-NAME, 30 mg/kg, i.p.) facilitated antinociception of this extract. Kaempferitrin was isolated and identified as major secondary metabolite. These results support the analgesic and spasmolytic-like activity of J. spicigera aerial parts involving inhibitory neurotransmission reinforcing the potential of this medicinal plant for alleviating pain.

Spasmolytic effect of aqueous extract of Tagetes erecta L. flowers is mediated through calcium channel blockade on the guinea-pig ileum.

This study provides pharmacological evidence on the spasmolytic activity of Tagetes erecta L. (marigold or cempasúchil) on the guinea-pig ileum and presents data on its mechanism of action. The relaxant effect on KCl contractions was more marked with aqueous (AqEx) than with ethanol extracts (EtEx) of T. erecta flowers (55.6 ±â€¯11.0 vs 21.1 ±â€¯4.4%, respectively). In addition, the aqueous extract antagonized contractions elicited by EFS, but not by acetylcholine (73.5 ±â€¯1.9 vs 14.5 ±â€¯5.3%, respectively). These effects were not diminished by hexamethonium or L-NAME, but this extract caused a rightward shift in the Ca2+ concentration-response curves like that of verapamil. Quercetin and rutin, two flavonoids present in this plant, also showed spasmolytic effects (95.7 ±â€¯2.8 and 27.9 ±â€¯7.1%, respectively). Interestingly, in tissues without spasmogens, the extract induced contractions superimposed on their spontaneous activity. These results support the traditional use of T. erecta as a spasmolytic in folk medicine and suggest mainly that quercetin could be partly responsible for this effect. The spasmolytic effect appears to involve voltage-gated calcium channels, but not the nitric oxide pathway or the release of neurotransmitters from enteric neurons. Nevertheless, this plant could produce colic or stomachache as adverse effects in clinical situations in which these symptoms are not originally present.

Acute toxicity and mutagenic activity of Mexican plants used in traditional medicine.

The present work was undertaken to determine safety parameters of selected Mexican medicinal plants chosen on the basis of their frequency of medicinal use and commercial importance. The medicinal herbs included Amphipteryngium adstringens, Hintonia standleyana, Hintonia latiflora, Piper sanctum, Haemathoxylon brasiletto, Iostephane heterophylla, Valeriana procera, Arracacia tolucensis, Brickellia veronicaefolia, Scaphyglottis livida, Exostema caribaeum, Hippocratea excelsa, Ligusticum porteri, Poliomintha longiflora and Gnaphalium sp. In the acute toxicity studies in mice performed according to the Lorke procedure, Exostema caribaeum, Hippocratea excelsa, Ligusticum porteri and Poliomintha longiflora were the most toxic with LD(50) values between 1085 and 2mg/kg. The Ames test revealed that Gnaphalium sp. and Valeriana procera extracts induced mutations of S. typhimurium TA98 with or without the S9 microsomal fraction, and TA100 in the presence of the enzymatic fraction, respectively. The tincture of Valeriana procera, however, was non-mutagenic. Finally, in the Artemia salina lethality test Brickellia veronicaefolia, Arracacia tolucensis, Poliomintha longiflora and Piper sanctum caused significant mortality of the crustacean larvae with LC(50) in the range of 37-227 microg/mL.

Spasmogenic and spasmolytic activities of Agastache mexicana ssp. mexicana and A. mexicana ssp. xolocotziana methanolic extracts on the guinea pig ileum.

ETHNOPHARMACOLOGICAL RELEVANCE: Agastache mexicana has been used in traditional medicine for relief of abdominal pain and treatment of other diseases. Two subspecies have been identified: A. mexicana ssp. mexicana (AMM) and A. mexicana ssp. xolocotziana (AMX) and both are used traditionally without distinction or in combination. AIM OF THE STUDY: To determine the effect of methanol extracts of A. mexicana ssp. mexicana and A. mexicana ssp. xolocotziana on gut motility and their possible mechanism of action. MATERIALS AND METHODS: The effect of AMM and AMX methanol extracts were tested on the spontaneous activity in the isolated guinea pig ileum and on tissues pre-contracted with KCl, electrical field stimulation (EFS) or ACh. In addition, the possible mechanism of action of each subspecies on gut motility was analyzed in the presence of hexametonium, indomethacin, L-NAME, verapamil, atropine or pyrylamine. A comparative chromatographic profile of these extracts was also done to indicate the most abundant flavonoids presents in methanol extracts of both subspecies. RESULTS: AMM, but not AMX, induced a contractile effect in the guinea pig ileum. This spasmogenic effect was partially inhibited by atropine, antagonist of muscarinic receptors; and pyrilamine, antagonist of H1 receptors. In contrast, AMX, but not AMM, diminished the contractions induced by KCl, EFS or ACh. The spasmolytic activity of AMX was partially inhibited by hexamethonium, ganglionic blocker; and indomethacin, inhibitor of the synthesis of prostaglandins; but not by L-NAME, inhibitor of nitric oxide synthase. In addition, AMX diminished the maximal contraction induced by CaCl2 in a calcium-free medium. Chromatographic analyses of these methanol extracts showed the presence of acacetin and tilanin in both. CONCLUSIONS: These results suggest that in folk medicine only AMX should be used as spasmolytic, and not in combination with AMM as traditionally occurs, due to the spasmogenic effects of the latter. In addition, activation of nicotinic receptors, prostaglandins and calcium channels, but not nitric oxide mechanisms, could be responsible for the spasmolytic activity of AMX. On the other hand, release of ACh and histamine could be involved in the spasmogenic effect induced by AMM. Acacetin and tilanin are present in methanol extracts of both subspecies and both flavonoids were more abundant in AMX than AMM. Our findings contribute to the validation of the traditional use of Agastache mexicana in relieving gastrointestinal disorders, but indicate that the subspecie that should be used for this effect is A. mexicana ssp. xolocotziana.

Neuroprotective effects of Tilia americana var. mexicana on damage induced by cerebral ischaemia in mice.

Tilia americana var. mexicana (T. americana) is a plant widely used in Mexico for its medicinal properties on the central nervous system. In the present study, we designed a protocol to investigate the neuroprotective effects of non-polar and polar extracts of T. americana on damage induced by cerebral ischaemia in mice. Vehicle or extracts were administered immediately after ischaemia. Functional neurological deficit, survival percentage and infarct area were determined in each experimental group. Results showed that groups treated with non-polar or polar extracts of T. americana had increased survival rate, improved neurological deficits and diminished the infarct area in relation to the ischaemic group. In conclusion, this study confirms the neuroprotective activity of T. americana, suggests a possible synergism between non-polar and polar constituents and supports its potential as a useful aid in the clinical management of stroke.