A família Myrtaceae é considerada uma das maiores famílias botânicas e o gênero Psidium está entre os de maior interesse econômico. Este trabalho tem como objetivo revisar aspectos botânicos, químicos e farmacológicos sobre o gênero Psidium. Os dados foram obtidos de artigos indexados nas bases Periódicos Capes, NCBI, Bireme e SciELO. Suas espécies podem ter folhas simples e opostas, flores solitárias, e frutos com muitas sementes. Dentre as principais propriedades farmacológicas, destacam-se as anti-inflamatórias, antimicrobianas e antioxidantes. As espécies conhecidas de maior importância econômica são: P. guajava, P. cattleianum e P. guineense que, por esse motivo, são as mais estudadas. Palavras-chave: Psidium; composição química e atividades farmacológicas.The Myrtaceae family is considered one of the largest botanical families and Psidium genus is among the highest economic interest. This work has as objective to review aspects botanical, chemical and pharmacological about Psidium genus. The data were obtained from articles indexed in databases Periodicals Capes, NCBI, Bireme and SciELO. Its species may have simple and opposite leaves, solitary flowers, and fruit with many seeds. The main pharmacological properties there are the anti-inflammatory, antimicrobial and antioxidant. The species among the most economically important are: P. guajava, P. cattleianum and P. guineense for this reason it is the most studied.

Psidium myrsinites DC. is species known as "araçá", from the Cerrado (savanna) biome in Brazil. It is commonly used as a medicinal plant in the treatment of diarrhea because of its astringent properties. The aims of this study were to carry out phytochemical screening with an exploratory purpose; to investigate toxicity by brine shrimp (Artemia salina) lethality bioassay; and to evaluate antimicrobial activity against Gram-positive and Gram-negative bacteria by determining the minimum inhibitory concentration of the essential oil, acetonic and ethanolic crude extracts, and the fractions obtained with organic solvents of Psidium myrsinites DC. leaves. The phytochemical profile determined the major classes of secondary metabolites present as phenolic compounds (tannins, coumarins, flavonoids, anthraquinone glycosides and terpene compounds). The essential oil and hexane fraction demonstrated a level of strong and mild toxicity respectively, thus encouraging further research with isolated substances from them. The crude ethanolic and acetonic extracts, and hexane fractions, chloroform intermediary, ethyl acetate and aqueous fraction from crude acetonic extract showed the best inhibitory effect on bacterial growth of Gram-positive bacteria with minimum inhibitory concentrations ranging between 62.5 and 250 µg.mL -1 . However, the presence of secondary compounds such as tannins, flavonoids and terpenes is probably associated with the inhibitory effect on tested microorganisms, which could justify the medicinal use of the leaves of this species.