Abstract:
Background: World Health Organization indicates that 70-80% of the world's population rely
on plant based traditional medicine but their toxicological properties have not been explored
adequately. Brine shrimp lethality assay is used in preliminary assessment of toxicity.
Clarkson's toxicity criterion classifies plant extracts with LC50≥1000 ppm; non-toxic, LC50 500–
1000 ppm; low toxic, LC50 100-500 ppm; medium-toxic, and extracts with LC50≤100 ppm are
very toxic. Leaves of Psidium guajava (Guava), Garcinia quaesita (Garcinia) and barks of
Cinnamomum verum (Cinnamon) are selected as those plant extracts are known to have anti diabetic properties and can be incorporated into functional food and nutraceuticals.
Objectives: To evaluate cytotoxicity of leaves of Psidium guajava (Guava), Garcinia quaesita
(Garcinia) and barks of Cinnamomum verum (Cinnamon) using Brine shrimp assay.
Methods: Aqueous extracts of guava and garcinia leaves and cinnamon-barks were freeze dried. Serial dilution of garcinia, cinnamon (10, 100, 250, 500, 750, and 1000 ppm) were
prepared. In addition, dilutions of guava were prepared up to 5000 ppm with 1000 intervals.
Brine shrimps were hatched in artificial sea water with dry Artemia salina cysts. After
incubation, the nauplii were separated into petri-dishes with 4 mL of artificial seawater.
Dimethyl sulfoxide (DMSO) and artificial sea water were used as positive and negative control,
respectively. LC50 were calculated with the number of dead nauplii at 24-hours using probit
regression analysis with SPSS software.
Results: None of the brine shrimp nauplii died with guava up to 1000 ppm. Average of 28.5
nauplii died from 2000 to 5000 ppm. The numbers of dead nauplii in ascending order of 10,
100, 250, 500, 750, and 1000 ppm garcinia concentrations were 22, 26, 30, 28, 30 and 30,
respectively. In cinnamon, it was 03, 04, 09, 09, 12 and 16, respectively. All the nauplii died in
the positive control and all nauplii alive in the negative control. LC50 of leaves of guava,
garcinia and barks of cinnamon were 1660, 2.2, and 1642 ppm, respectively.
Conclusions: This study reveals that aqueous extracts of guava-leaves and cinnamon-bark are
non-toxic, whereas garcinia-leaves demonstrated toxicity in brine shrimp assay.
