Accelerators Use for Irradiation of Fresh Medicinal Herbs

The paper presents the results regarding the electron beam irradiation of fresh Salvia Officinalis and Calendula Officinalis. Irradiation is already a well-known decontamination method, but it received less attention for medicinal plants, especially on fresh herbs. Microbial load behaviour, antioxidant activity, and enzymatic inhibition activity were measured for doses up to 50 kGy. Herbs are decontaminated without any important alteration in the active principles up to 1 kGy, but they loose their fresh aspect easier than non-irradiated ones. The last effect could be useful for the extracting process in which herbs are stressed anyway. INTRODUCTION Microbiological contamination of medicinal herbs is a serious problem in the production of therapeutical preparations. A good quality of the product according to pharmaceutical requirements may be achieved by different methods of decontamination. Decontamination treatments should be fast and effective against all microorganisms [1]. The conventional methods of decontamination were fumigation with gaseous ethylene oxide or methyl bromide, which are now prohibited or being increasingly restricted in most advanced countries for health, environmental or occupational safety reasons. [2, 3] Treatment by ionising radiation is already a wellknown decontamination method [4], but it received less attention for medicinal plants [5], especially on fresh herbs. Irradiation is technically feasible, very effective and friendly enough to environment process. The paper presents the results regarding the electron beam irradiation of some fresh herbals, Salvia Officinalis and Calendula Officinalis. EXPERIMENTAL Samples Fresh unwashed green herbs, Salvia Officinalis and Calendula Officinalis were purchased from Hofigal S. A., which is the main Romanian manufacturer of natural products. Irradiation The samples were irradiated in plastic package at room temperature in accelerated electron beams from a linear electron accelerator (ALIN – 10) built in our institute. The ALIN-10 electron accelerator is of travelling-wave type, operating at a wavelength of 10 cm and it generates electron beam pulses of 4 μs duration, 6 MeV mean energy and 75 mA current peak intensity, at a repetition frequency of 50 Hz to 100 Hz. The dose rate at 50 cm from the scattered exit window is up to 4.6 kGy/minute. It was obtained doses up to 50 kGy. Sample analysis a. Microbiological analysis: Microbial contamination was measured according to the method described by Romanian Pharmacopoeia [6]. b. Antioxidant activity determination: Antioxidant activity was identified by means of biochemical measurement of lipid peroxidation (LPO) and both enzymatic (superoxide dismutase – SOD) in guinea pig brain homogenate. Inhibition of lipid peroxidation was estimated using a technique based on the measurement of the malonaldehyde concentration using thiobarbituric acid (TBA), which generates a colored product. The spectrophotometrical detection of this colored product was made at λ = 532 nm. Activity of SOD (EC. 1.15.1.1) was determined by standard method, following the catching action of free radicals in a generating system of them. c. Inhibition of some enzymes: Inhibition of hyaluronidase was performed by ELISA method using hyaluronic acid as substrat and it is quantified spectrophotometrically at λ = 595 nm. Phospholipase A2 (PLA2) inhibition were performed macroscopically using lechitin included in an agarose gel. RESULTS AND DISSCUSSION Microbial load determination Fresh Salvia Officinalis had 1x10 microorganisms/g, and these microorganisms were identified as bacteria and moulds (Rhizopus, Mucor and Penicilium). After irradiation with 0.2 kGy, the bacteria were decreased at 1x10/g and moulds were destroyed. No microorganisms were survived after irradiation with 0.5 kGy (see Table 1). Table 1: Microbial load for Salvia officinalis Dose, kGy 0 0.2 0.5 1 2 5 10 20 50 Microbial load/g 10 10 0 0 0 0 0 0 0 ___________________________________________ [email protected] Proceedings of EPAC 2004, Lucerne, Switzerland