Objective: The antioxidant capacity of Aloysia citriodora Palau samples also known as “fake balm, lemon scented melissa, lemon balm”, purchased from herbalists in different provinces of our country was aimed to be determined. In this context, total amount of phenolic compounds of the samples were calculated. Additionally, compliance of the samples sold in the market, to the public health was evaluated in terms of microbiological contamination.

Material and Method: In this study, 11 different samples were purchased from four different provinces. Besides standard samples were obtained from Yalova and were dried under suitable conditions. Antioxidant capacity of the samples was examined by two different methods: 1. Qualitative and quantitative DPPH• (2,2-diphenyl-1- picrylhydrazyl) method for determination of free radical scavenging capacity, 2. TBA (thiobarbituric acid) method for the determination of liposome lipid peroxidation. Total phenol content of the samples was also determined as gallic acid equivalent by using Folin- Ciocalteu method. Microbiological contamination of the samples was examined according to the European Pharmacopoeia.

Results: Total phenol content in the samples was determined as gallic acid equivalence of 213-483.56 mg/g dry weight. In qualitative DPPH• method, standard sample showed significant free radicalscavenging capacity, while in quantitative DPPH• method, this sample showed lower capacity than propyl gallate. In the TBA method, highest lipid peroxidation capacity was determined for the samples purchased from İstanbul market (İ1). In the studied samples, the growth of pathogenic microorganisms was not observed. However, number of microorganisms have been found to be higher than the limits provided in the European Pharmacopoeia.

Conclusion: Total phenolic content and antioxidant capacity of the drugs sold on the market vary. The samples of lemon balm purchased in the market were found unsuitable for use on human health because of the presence of microorganisms above the limits accepted by European Pharmacopoeia. In this study the compliance to European Pharmacopoeia of Aloysia citriodora Palau samples sold in our various provinces in terms of microbiological contamination was assessed for the first time.