Data/hora: 09/06/2024 07:29:58

Provedor de dados: 	Ciência Rural	
País: 	Brazil	
Título: 	Harvest time on the content and chemical composition of essential oil from leaves of guava	
Autores: 	Silva,Elizabeth Aparecida Josefi da; Silva,Vanessa Paula da; Alves,Cassia Cristina Fernandes; Alves,José Milton; Souchie,Edson Luiz; Barbosa,Luiz Cláudio de Almeida.	
Data: 	2016-10-01	
Ano: 	2016	
Palavras-chave: 	Psidium guajava L.; Medicinal plants; Special metabolites; Α-humulene; Trans-caryophyllene; Guava.	
Resumo: 	ABSTRACT: The essential oil plants contents can be affected by several factors. For example, in certain plants, collection time has been observed to affect the content and chemical composition of the essential oil obtained from the plant. The objective of this study was to evaluate the effect of collection time on the content and chemical composition of the essential oil from guava ( Psidium guajava L.) leaves. Leaves were collected at different times of the day and the content and chemical composition of their essential oil was determined. Collection time did not qualitatively affect the chemical composition of the essential oil. However, concentration of certain substances in the oil, such as α-humulene and trans-caryophyllene, did significantly vary at different collection times. The main constituents of the essential oil of  Psidium guajava are limonene (2.2-4.4%), trans-caryophyllene (18.1-17.1%), α-humulene (26.3-20.4%), aromadendrene (7.6-12.2%), α-selinene (7.3-11.3%), caryophyllene oxide (3.7-3.3%), humulene epoxide II (4.1-1.9%), and selin-11-en-4α-ol (7.2-11.1%). Leaves collected at 7:00 AM had higher essential oil production, with a content of 0.38% (d.b.), whereas leaves collected at 7:00 PM had lower essential oil production, 0.24% (d.b.). Chemical analysis showed that sesquiterpene compounds represented the highest concentration (62.0%), and monoterpenoids and monoterpenes represented the lowest concentrations (1.1 and 2.2%, respectively). Chemical classes that underwent major changes with respect to collection time were monoterpenes, sesquiterpenes, and sesquiterpenoids (2.2-4.4%, 63.8-61.7%, and 15.9-13.2%, respectively).	
Tipo: 	Info:eu-repo/semantics/article	
Idioma: 	Inglês	
Identificador: 	http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782016001001771	
Editor: 	Universidade Federal de Santa Maria	
Relação: 	10.1590/0103-8478cr20150947	
Formato: 	text/html	
Fonte: 	Ciência Rural  v.46 n.10 2016	
Fonte: 	info:eu-repo/semantics/openAccess