Annona muricata L (Annonaceae), commonly known as soursop has a long, rich history in herbal medicine with a lengthy recorded indigenous use. It had also been found to be a promising new anti-tumor agent in numerous in vitro studies. The present investigation concerns chemopreventive effects in a two-stage model of skin papillomagenesis. Chemopreventive effects of an ethanolic extract of A. muricata leaves (AMLE) was evaluated in 6-7 week old ICR mice given a single topical application of 7,12-dimethylbenza(α)anthracene (DMBA 100 μg/100 μl acetone) and promotion by repeated application of croton oil (1% in acetone/ twice a week) for 10 weeks. Morphological tumor incidence, burden and volume were measured, with histological evaluation of skin tissue. Topical application of AMLE at 30, 100 and 300 mg/kg significantly reduced DMBA/croton oil induced mice skin papillomagenesis in (i) peri-initiation protocol (AMLE from 7 days prior to 7 days after DMBA), (ii) promotion protocol (AMLE 30 minutes after croton oil), or (iii) both peri-initiation and promotion protocol (AMLE 7 days prior to 7 day after DMBA and AMLE 30 minutes after croton oil throughout the experimental period), in a dose dependent manner (p<0.05) as compared to carcinogen-treated control. Furthermore, the average latent period was significantly increased in the AMLE-treated group. Interestingly, At 100 and 300 mg/ kg, AMLE completely inhibited the tumor development in all stages. Histopathological study revealed that tumor growth from the AMLE-treated groups showed only slight hyperplasia and absence of keratin pearls and rete ridges. The results, thus suggest that the A.muricata leaves extract was able to suppress tumor initiation as well as tumor promotion even at lower dosage.
Ardisia crispa (Family: Myrsinaceae) has been used as a traditional medicine for various ailments. Previous studies showed that Ardisia crispa possesses antimetastatic and anti-inflammatory properties. Nevertheless, research done on the plant is still limited. Therefore, the present study was designed to evaluate the suppression effect of Ardisia crispa root hexane (ACRH) extract on 7, 12-dimethylbenz (α) anthracene (DMBA)-induced mice skin tumor promotion in ICR mice with topical application twice weekly for 10 weeks. Results showed significant difference between treatment groups (mice treated with 30 mg/kg, 100 mg/kg and 300 mg/kg of ACRH extract; denoted as group I, II and III respectively) for tumor incidence and tumor burden (P<0.05). Significant reduction in tumor incidence (20%), tumor burden (1.5 ± 0.50), tumor volume (2.49 ± 1.70) and delayed latency period of tumor formation was observed in group I (30 mg/kg) in comparison to carcinogen control. This study indicates that ACRH extract could be a promising skin tumor promotion suppressing agent at a lower dosage (30 mg/kg). Further studies are required to elucidate the underlying mechanism(s) leading to this effect.
CONTEXT: Ardisia crispa Thunb. A. DC (Myrsinaceae) or locally known as hen's eyes has been used in local folk medicine as a remedy in various illnesses. Previously, it has been reported to inhibit various inflammatory diseases. However, research done on this plant is still limited.
AIMS: In the present study, the hexane fraction of the A. crispa root (ACRH) was evaluated on the peri-initiation and promotion phases of skin carcinogenesis.
MATERIALS AND METHODS: This two-stage skin carcinogenesis was induced by a single topical application of 7,12-dimethylbenz(α)anthracene (DMBA) and promoted by repeated treatment with croton oil for 10 weeks in Imprinting Control Region (ICR) mice. Morphological observation would be conducted to measure tumor incidence, tumor burden, and tumor volume. Histological evaluation on the skin tissue would also be done.
RESULTS: The carcinogen control group exhibited 66.67% of tumor incidence. Although, in the ACRH-treated groups, at 30 mg/kg, the mice showed only 10% of tumor incidence with a significant reduction (P < 0.05) in the values of tumor burden and tumor volume of 2.00 and 0.52 mm(3), respectively. Furthermore, the result was significantly lower than that of the carcinogen and curcumin control. At 100 mg/kg, ACRH showed a comparable result to carcinogen control. On the contrary, at 300 mg/kg, ACRH exhibited 100% tumor incidence and showed a significant elevated (P < 0.05) value of tumor burden (3.80) and tumor volume (14.67 ± 2.48 mm(3)).
CONCLUSIONS: The present study thus demonstrates that the anti-tumor effect of the chemopreventive potential of ACRH is at a lower dosage (30 mg/kg bwt) in both the initiating and promotion period, yet it exhibits a promoting effect at a higher dosage (300 mg/kg bwt).