Diversidade de angiospermas e espécies medicinais de uma área de Cerrado / Angiosperm diversity and medicinal species of Cerrado area

RESUMO Este trabalho teve como objetivo conhecer a diversidade vegetal de uma área de Cerrado em Prudente de Morais, MG, bem como suas indicações medicinais. Foram feitas nove excursões à reserva da Fazenda Experimental Santa Rita da Empresa de Pesquisa Agropecuária de Minas Gerais (FESR/EPAMIG) (19°26’20”’ S e 44°09’15”’ W). O material vegetal coletado foi herborizado, identificado e incorporado ao acervo do Herbário PAMG/EPAMIG. O sistema de classificação utilizado foi o APG III. Após a identificação, realizou-se uma pesquisa bibliográfica buscando dados sobre a utilização medicinal das espécies. Coletaram-se 108 espécies pertencentes a 47 famílias. As famílias mais representativas foram: Fabaceae, com 16 espécies, Myrtaceae com sete espécies, Asteraceae e Rubiaceae com seis espécies cada, Malpighiaceae e Solanaceae com cinco espécies cada, Erythroxylaceae, Euphorbiaceae e Vochysiaceae, com quatro espécies cada, Anacardiaceae, Apocynaceae, Lamiaceae e Sapindaceae com três espécies cada, Annonaceae, Arecaceae, Bignoniaceae, Celastraceae e Primulaceae com duas espécies cada. Vinte e nove famílias foram monoespecíficas. Das 108 espécies, 39 são árvores (36%), 43 arbustos (40%), seis subarbustos (5,5%), 14 lianas (13%) e seis são ervas (5,5%). Sessenta e seis (61%) espécies pertencentes a 39 famílias (83%) são utilizadas popularmente, para o tratamento de alguma doença. As famílias com maior número de espécies medicinais foram: Fabaceae com oito espécies; Rubiaceae com cinco espécies e Solanaceae com quatro espécies. As espécies que apresentaram mais finalidades terapêuticas foram: Brosimum gaudichaudii Trécul (Moraceae), Caryocar brasiliense Cambess. (Caryocaraceae), Cochlospermum regium (Mart. ex Schrank) Pilg. (Bixaceae), Croton urucurana Bail. (Euphorbiaceae), Gomphrena officinalis Mart. (Amaranthaceae), Hymenaea stigonocarpa Mart. ex Hayne (Fabaceae), Lithrea molleoides (Vell.) Engl. (Anacardiaceae), Myracrodruon urundeuva Allemão (Anacardiaceae) e Randia. armata (Sw.) DC. (Rubiaceae). As finalidades terapêuticas que apresentaram maior número de espécies foram: tônico (15 spp., 22,7%), afecções do aparelho respiratório (13 spp., 19,6%), afecções da pele (12 spp., 18%) e febres (12 spp., 18%). O conhecimento tradicional sobre as plantas medicinais do cerrado deve ser mais investigado para que seja preservado, valorizado, e para que medidas conservacionistas sejam tomadas evitando que essas plantas desapareçam antes que sua utilização tradicional seja corroborada pela ciência.

ABSTRACT This study aimed to investigate the plant diversity of a Cerrado area in Prudente de Morais, MG, and its medicinal indications. Nine field trips were made to the reserve of Fazenda Experimental Santa Rita of the Empresa de Pesquisa Agropecuária de Minas Gerais (FESR/EPAMIG) (19°26’20” S and 44°09’15” W). The plant material collected was herborized, identified and incorporated into the collection of the Herbarium PAMG/EPAMIG. The classification system used was the APG III. After identification, we carried out a literature search to find data about the medical use of the species. 108 species were collected, belonging to 47 families. The most representative families were Fabaceae, with 16 species, Myrtaceae with seven species, Asteraceae and Rubiaceae with six species each, Malpighiaceae and Solanaceae with five species each, Erythroxylaceae, Euphorbiaceae and Vochysiaceae, with four species each, Anacardiaceae, Apocynaceae, Lamiaceae and Sapindaceae with three species each, Annonaceae, Arecaceae, Bignoniaceae, Celastraceae and Primulaceae with two species each. Twenty-nine families were monoespecific. From the 108 species, 39 are trees (36%), 43 are shrubs (40%), six are subshrubs (5.5%), 14 are climbing (13%) and six are herbs (5.5%). Sixty-six (61%) species belonging to 39 families (83%) are commonly used for the treatment of diseases. The families with the highest number of medicinal species were the Fabaceae with eight species; the Rubiaceae with five species and the Solanaceae with four species. The species showing more therapeutic purposes were: Brosimum gaudichaudii Trécul (Moraceae), Caryocar brasiliense Cambess. (Caryocaraceae), Cochlospermum regium (Mart. Ex Schrank) Pilg. (Bixaceae), Croton urucurana Bail. (Euphorbiaceae), Gomphrena officinalis Mart. (Amaranthaceae), Hymenaea stigonocarpa Mart. ex Hayne (Fabaceae), Lithrea molleoides (Vell.) Engl. (Anacardiaceae), Myracrodruon urundeuva Allemão (Anacardiaceae) and Randia. armata (Sw.) DC. (Rubiaceae). The therapeutic purposes indicated by the highest number of species were: tonic (15 spp., 22.7%), diseases of the respiratory system (13 spp., 19.6%), skin affections (12 spp., 18%) and fever (12 spp., 18%). The traditional knowledge of medicinal plants of the Cerrado should be investigated further in order to be preserved and enhanced. In that sense, conservation measures should be taken for these plants do not disappear before their traditional use is supported by science.

Temporal variation of chemical composition and relaxant action of the essential oil of Ocimum gratissimum L. (Labiatae) on guinea-pig ileum.

The medicinal plant Ocimum gratissimum L. (Labiatae) is widely encountered in the Northeast of Brasil where it is used to treat digestive problems. Its leaves have an essential oil (EOOG) content whose chemical composition varies according to the time of plant collection. We have compared the effects of the EOOG, collected at 08:00 a.m. (EOOG8) and at 12:00 a.m. (EOOG12), on the relaxation of guinea-pig isolated ileum. Both EOOG8 and EOOG12 (30-300 microg/ml) reversibly relaxed the spontaneous tonus of the guinea-pig ileum in a concentration-dependent manner, with similar IC50 values (49.3 and 23.8 microg/ml, respectively). The magnitude of the decrease in resting tonus was similar to that of the recognised smooth muscle relaxant papaverine. EOOG8 and EOOG12 relaxed 60 mM KCl-precontracted preparations similarly (38.33 +/- 9.91 microg/ml and 35.53 +/- 6.70), whereas a significantly more potent relaxant effect of EOOG12 compared to EOOG8 was observed when tissues were contracted using 10 microM acetylcholine (IC50 values of 69.55 +/- 4.93 and 128.16 +/- 15.70 microg/ml, respectively; p < 0.05). The principal constituents of the essential oil, eugenol and cineole, also relaxed KCl-precontracted preparations, although they were less potent than EOOG, suggesting that they alone were not responsible for EOOG-induced relaxations. Our results show that the essential oil extracted from the leaves of O. gratissimum L., collected at different time periods, exerts significant relaxant effects on isolated guinea-pig ileum which may underlie the therapeutic action of the plant.

Antinociceptive properties of the essential oil of Ocimum gratissimum L. (Labiatae) in mice.

We have investigated the antinociceptive effects of the essential oil of Ocimum gratissimum L. (Labiatae) (EOOG) in two classical models of pain in male Swiss mice (25-35 g), the writhing test and the formalin test. At doses of 30, 100 and 300 mg/kg (po), EOOG produced a dose-dependent inhibition (from 58.3 4.4 to 40.7 6.3, 36.4 3.6 and 24.6 3.6, respectively; N = 8-10, P<0.05) of acetic acid-induced writhing, causing up to a ~60% inhibition at the highest dose used, comparable to that obtained with indomethacin (10 mg/kg, po). At the same doses, EOOG predominantly inhibited the late (inflammatory) phase of the formalin-induced pain response (from 59.3 8.3 to 40.4 4.8, 23.2 2.8 and 25.3 5.5, respectively; N = 6, P<0.05), with a maximal reduction of ~60% of the control, although a significant reduction of the initial (neurogenic) phase was also observed at 300 mg/kg (from 62.5 6.07 to 37 5.9; P<0.05). On the basis of these data, we conclude that EOOG possesses interesting antinociceptive properties in the writhing and formalin tests. Due to the relatively low toxicity of EOOG, further detailed examination is strongly indicated for a better characterization of its pharmacological properties and its potential therapeutic value.