RESUMO:As plantas medicinais vêm sendo cada vez mais utilizadas devido às suas propriedades preventivas, paleativas e curativas, além de ser uma terapia alternativa que traz inúmeros benefícios aos usuários. As espécies Mikania glomerata e M. laevigata pertencem à família Asteraceae e são popularmente conhecidas como guaco sendo utilizadas no tratamento de enfermidades do trato respiratório. Além disso, as duas espécies são frequentemente confundidas ou citadas na literatura de forma errada. O presente trabalho teve por objetivo realizar uma revisão bibliográfica sobre a farmacologia, farmacobotânica e fitoquímica dos metabólitos secundários de Guaco, tendo destaque a cumarina, a biossíntese e as ações biológicas. As ações broncodilatadora, expectorante, anti-inflamatória e antialérgica, além de interações com alguns antibióticos e anticoagulantes, também foram descritas neste estudo. Palavras-chave: fitoterapia, guaco, metabólitos secundários, biossínteseABSTRACT: Morpho-anatomy, phytochemistry and pharmacology of Mikania glomerata Sprengel: a brief literature review. Medicinal plants have been increasingly used due to their preventive, palliative and curative properties, besides being an alternative therapy that brings a large number of benefits to their users. The species Mikania glomerata belongs to the Asteraceae family and is popularly known as guaco, being employed to treat diseases of the respiratory tract. This study aimed to carry out a literature review about the pharmacology, pharmacobotany and phytochemistry of the secondary metabolites of M. glomerata, particularly coumarin, its biosynthesis and biological actions. The bronchodilator, expectorant, anti-inflammatory and antiallergic actions, as well as the interactions with some antibiotics and anticoagulants, were also described in this study. Key words: phytotherapy, guaco, secondary metabolites, biosynthesis INTRODUÇÃOHá muito tempo as plantas medicinais vêm sendo estudadas na tentativa de descoberta de novos princípios ativos. Plantas medicinais são assim chamadas por apresentarem propriedades curativas e/ou preventivas para determinadas doenças.As referências históricas afirmam que o uso de plantas medicinais faz parte da evolução humana e que essa prática é relatada na maioria das antigas civilizações, sendo a primeira referência escrita encontrada na obra Pen Ts'ao "A Grande Fitoterapia", do chinês Shen Nung, a qual remonta a 2800 a.C (Dorta, 1998). A fitoterapia foi um dos primeiros recursos terapêuticos utilizados pelos povos, além de ser por muito tempo a única terapia disponível ao homem. Em algumas ocasiões as plantas curavam, em outras matavam ou produziam graves efeitos colaterais (De Melo et al., 2009), sendo, portanto, essencial o uso responsável, racional, seguro e não abusivo das mesmas.Fitoterapia significa tratamento de uma dada doença mediante o uso de plantas. Pode-se dizer então que a fitoterapia é uma terapêutica caracterizada pelo uso de plantas medicinais nas diferentes formas farmacêuticas. Emitida pela Agência Nacional de...

Based on these results, we can conclude that disaccharidases are targets of flavonoids in the regulation of glucose absorption and consequently glucose homeostasis.

A stimulatory effect of apigenin-6-C-β-fucopyranoside (1) on glucose uptake was observed when rat soleus muscle was incubated with 1, 10 and 100 μM of this flavonoid glycoside. The presence of specific insulin signaling inhibitors, such as wortmannin, an inhibitor of phosphoinositide 3-kinase (PI3K), RO318220, an inhibitor of protein kinase C (PKC), PD98059, an inhibitor of mitogen-activated protein kinase (MEK), and HNMPA(AM)₃, an insulin receptor tyrosine kinase activity inhibitor showed that apigenin-6-C-β-fucopyranoside triggers different metabolic pathways in skeletal muscle. The oral administration of crude extract, fractions and isolated flavonoids (apigenin-6-C-β-fucopyranoside (1) and apigenin-6-C-(2″-O-α-rhamnopyranosyl)-β-fucopyranoside (2)) from Averrhoa carambola leaves exhibited a potential hypoglycemic activity in hyperglycemic normal rats. Additionally, both flavonoids significantly increased the muscle and liver glycogen content after an acute treatment. The results indicate that A. carambola can be regarded as a potent antihyperglycemic agent with insulin secretagogue and insulin mimetic properties.

The similarities of rutin action on glucose uptake compared with the signalling pathways of insulin constitute strong evidence for the insulin-mimetic role of rutin in glucose homeostasis.

In this study we examined the acute in vivo effect and short- and long-term in vitro effects of samples from native and commercial Ilex paraguariensis on glucose homeostasis. Also, the potential effect of I. paraguariensis on serum insulin secretion was investigated. The chemical identification and quantification of methyl xanthines and polyphenols in CH₂Cl₂, EtOAc and n-BuOH fractions of native I. paraguariensis as well as infusions of green and roasted I. paraguariensis from a commercial source was verified by high-performance liquid chromatography. The results for the serum glucose-lowering indicated that both fractions and both infusions were able to improve significantly the oral glucose tolerance curve. Additionally, both the EtOAc and n-BuOH fractions induced-insulin secretion, but EtOAc induced an early (at 15 min) and late (at 60 min) biphasic peak of insulin secretion similar to glipizide stimulatory effect. Both fractions increased liver glycogen content compared with fasted normal rats. Also, EtOAc and n-BuOH fractions inhibited in vitro disaccharidases activities after an acute treatment. The maximum inhibitory effect of the EtOAc and n-BuOH fractions on maltase activity (at 5 min) was around 35%. The evident reduction of protein glycation by glucose or fructose with EtOAc and n-BuOH fractions increased from 7 to 28 days of in vitro incubation. Inhibition of bovine serum albumin glycation by glucose and fructose, by around 50% and 90%, respectively, was observed. Additionally, the green and roasted mate infusions reduced the formation of AGEs in a characteristic long-term effect. In conclusion, this study shows that I. paraguariensis has an anti-hyperglycemic potential role able to improve the diabetic status and is probably a source of multiple hypoglycemic compounds.

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RESUMO:Fracionamento cromatográfi co da fração em diclorometano obtida do extrato etanólico das folhas de Vernonia tweediana Baker (Asteraceae) conduziu ao isolamento de α-amirina, β-amirina, lupeol, β-sitosterol, estigmasterol e espinasterol. As estruturas foram identifi cadas através de técnicas espectroscópicas usuais, além da comparação com dados relatados na literatura. Os compostos isolados são relatados pela primeira vez para a espécie V. tweediana. Unitermos:Vernonia tweediana, Asteraceae, triterpenos, esteróides.ABSTRACT: "Phytoconstituents isolated from dichloromethane fraction of Vernonia tweediana Baker leaves". Fractionation of the dichloromethane -soluble fraction from the ethanol extract of the leaves of Vernonia tweediana (Asteraceae) led to the isolation of α-amyrin, β-amyrin, lupeol, β-sitosterol, stigmasterol and spinasterol. The structures of the isolates were elucidated by spectroscopic analysis and comparison with literature data. The isolated compounds are reported for the fi rst time to the species V. tweediana.