Nigella sativa L., popular called fennel ﬂower, is an herbaceous plant of the Ranunculaceae family.1,2
Originary from countries in North Africa (Marocco, Egypt, Tunisia) and Middle Est (Syria, Jordan) where it grows spontaneously, the herb was acclimated in Romania by cultivation in Vladimirescu village, Arad county.3,4
For therapeutic purposes, the Nigella sativae semen is used, which is rich in volatile oils, fat acids, oligoelements, saponine elements, alkaloids and is used empirically as an antiallergic, antiasmatic, immunity and potency stimulant etc.1,5
Therapeutic uses determined cultivation of this plant in Romania as well.
For these vegetal products, above mentioned, with an already proved medical effect, to be used in therapeutic purposes, the international protocols have required studies which should test the acute and chronic toxicity of these products as well as studies which should exclude their radioactive contamination.
The studies regarding the two types of toxicity having already been performed, the next step is the assessment of the possible radioactive contamination, which is also the object of this study.
Because the soil where the plants grow, the rainwater and the possible radioactive deposits from the harvesting area could transfer to the vegetal material any type of radiation (α, β or γ). This fact would qualify the vegetal material as unacceptable from the therapeutic point of view, so, an investigation to establish the radioactivity parameter has been considered necessary.
MATERIAL AND METHOD
|Table 1. Results of statistical analysis of radioactivityspectrophotometer measures.
The vegetal product is represented by Nigellae sativae semen and Nigellae sativae herba, a crop of Calendulae herba cultivated in the same soil together with a soil sample taken from the cultivation area. Both the vegetal products and the soil sampling were taken off in June - July 2003 in Vladimirescu village, Arad county.
The plants were indoors dried, away from sunbeam and then dewatered in oven at 120˚ C (ETUVA) 100 up to the invariable weight (Table 1
The following step consists of sampling calcinations in a calcinations oven in order to get plant ash. Radioactive content was determined with α-β global and gamma spectrometric measures.8-13
This operation was done in the following devices: counter of alfa - beta particles FHT 1100 (Eberline) for α-β radiation and Oxford γ spectrophotometer with NaI probe to detect gamma radiations.14, 15
All determinations were repeated by six fold at the same conditions.
Alpha type radiation represented by α particles (protons and heavy ions) are not penetrating, but are dangerous when eaten. Penetrability is 3 - 4 cm in general, representing an extremely low external risk. Alpha type radiation can be stopped by interposing a paper sheet.
Beta type radiation are generated by electrons and positrons and have a rather slow penetrability in atmosphere, up approx. 10 m. Beta type radiations can be stopped by interposing a thin screen or an alluminium leaf.
Gamma activity is established by photons, particles with very high penetrability that are propagated in the atmosphere with light velocity. Gamma radiation is very dangerous, it cannot be blocked and therefore it is classiﬁed as very penetrating radiation gamma radiation.
The results obtained from the measuring activities are presented in Table 1, the detection limit of the two devices used to detect α, β and γ radiation are α - 0.09 Bq, β - 0.27 Bq and γglobal - 11Bq.
We should also mention the fact that radioactivity is measured in Bq/Kg.
There are no data referring to the Nigella radioactivity but there are plenty of other similar information about different other species with a medical value (Atropa, alge).15-17
Alpha activity of all three plants and soil as well is bellow detection limits (SLD).
Beta activity of the three plants was detectable and it ranges between 91.8 Bq/Kg at Nigellae sativae semen and 204 Bq/Kg at Calendulae herba.
The highest value was detected in the soil sample, which is 247 Bq/Kg.
The values of the beta activity measured for the three vegetable products and soil are below the limit of the values considered to be dangerous for people and animals, between 325-1100 Bq/Kg.8-12
As we can see in Table 1, only the soil presents γ radioactivity, but its value is below the limit of 300 - 800 Bq/ Kg, interval acknowledged by specialized publications to be radioactive.9,10,16
Gamma radiation value measured for the three plants is below detection limits (SLD), soil γ radiation value 184 Bq/Kg was permissible.
It is interesting to specify that soil does not transfer γ type radioactivity to the three plants, which is signiﬁcant for plants quality allowing therapeutic use without any risk.
Isotopes responsible for a radioactivity over detection limits may be: 3H, 40K, 60Co, 65Zn, 131I, 134Cs, 137Cs, 222Rn etc.
1. The radioactivity values recorded at the three plants are in permissible limits; therefore these plants are proper to be used in therapeutics products.
2. Among the three plants, the seeds of Nigella sativa L (Ranunculaceae) are least susceptible in collecting radiation.
3. The cultivation area presents a normal radioactivity, thus showing an absence of radioactive are in that particular area selected for plants cultivation.
4. The presence of gamma radiation in the soil and the lack of it in the analyzed plants indicates that the investigated species present a low susceptibility other sensitive and therefore more predisposed to contamination species.