Romeo C. Ongpoy., /JAASP 2017;6:1 RESEARCH PAPER The Medicinal Properties of the Alocasia Genus: A Systematic Review Romeo C. Ongpoy, Jr.1, 2, 3 1College of Pharmacy, De La Salle Health Sciences Institute; 2Regulatory, Clinical & Quality Department, PerkinElmer Instruments (Phils.) Corp. 3Graduate School, Centro Escolar University – Mendiola Abstract Keywords The objective of this study is to evaluate the existing medicinal studies of the Alocasia genus and identify the possible studies Alocasia that may be done in the future on its member species. To do Medicinal Properties Alocasia spp. this, Science Direct and Google Scholar were used as a database to get the available researches searching for the term Correspondence “Alocasia” and some of its common species like “Alocasia Romeo C. Ongpoy, Jr, macrorrhiza”. Fifty eight articles were selected and from these, College of Pharmacy, De La Salle 28 were qualified for this systematic review. Results show that Health Sciences Institute; Alocasia species are mostly studied for antioxidant and Regulatory, Clinical & Quality antitumor and cytotoxic studies and to some extent Department, PerkinElmer Instruments antimicrobial and glycemic and lipidemic studies which are (Phils.) Corp. Graduate School, Centro Escolar mostly related to cancer studies. The findings in this study University – Mendiola suggest that Alocasia species may be studied further for toxicities and most importantly, cancer ddestudies as based on E-mail: [email protected] available literatures, there is a strong pattern that correlates its available medicinal studies to the different stages of cancer development. 1. Introduction Alocasia species has also been known as vegetable apart from its ornamental purpose Alocasia genus is composed of tropical plants and medicinal properties like Alocasia indica with mostly showy large leaves. It is generally (Roxb.) Schott [5]. As mentioned, Alocasia referred to as Elephant’s ear for this reason grows in countries with tropical climate and [1]. While mostly used as ornamental, there is there are ethnopharmaceutical practices in a potential for medicinal use among its species most of these countries brought about by the as can be seen in this exhaustive systematic natives that may provide a good clue and review on its medicinal property where drug guidance in studying the genus. Like the use of discovery studies are slowly becoming popular Alocasia macrorrhiza (Linn.) in cough and for the genus. There are also new species that toothache [6] and as antimalarial [7] and are discovered from time to time giving the Alocasia indica (Roxb.) Schott for abscess [8] opportunity to study novel molecule like the and as a nyctalopic [9], these are few of the following species: Alocasia nycteris in the folkloric uses of the plants in the genus. Philippines [2], Alocasia hypnosa in China [3], Studying the plant onwards drug discovery is and those in Thailand like Alocasia hypoleuca, very important as a lot of species remain Alocasia longiloba, Alocasia navicularis and unexplored for medicinal purpose like the Alocasia perakensis [4]. endemic Alocasia sanderiana Bull. in the Philippines that have limited researches. 25 Romeo C. Ongpoy., /JAASP 2017;6:1 RESEARCH PAPER 2. Methodology epidermidis, Salmonella typhi, Shigella flexneri, Shigella sonnei and Shigella The word “Alocasia” was searched under dysentery. Using Alocasia fornicata leaves and Google Scholar and Science Direct and a total stolons (roots) in the study of Hague et al of 58 articles were retrieved last mid-June of [13], the chloroform, ethyl acetate and 2016. Out of the 58 articles, 9 were not ethanolic extracts of the said plant gave included due to non-medicinal topics about moderate-to-good antimicrobial activity with Alocasia like biotechnology, farming and an average zone of inhibition at 8-20 mm. chemical studies. Another 9 articles were excluded due to taxonomical, For antifungal studies, it has been identified ethnopharmaceutical and nutraceutical nature that Alocasin, may be the antifungal present in and were instead used as supplemental to this the rhizomes of Alocasia macrorrhiza as review. Ten articles were finally excluded isolated by Wang et al [14] which may justify because they only discuss Alocasia in part and the same antifungal activity in Alocasia odora not as the main topic of the study, these methanolic extract using its leaf, rhizome and studies were also used as a supplemental to leafstalk as reported by Wang et al [15] which this article instead. A total of 28 articles were gave an overall 89.12% inhibition using the used for this systematic review that may add trichloromethane extract at 10 mg/mL against knowledge to the medicinal use of the Alocasia various fungal specimens. genus. 3.2. Antioxidant Studies 3. Results Antioxidant property is one of the most studied There are very few medicinal studies done on Alocasia medicinal use. Among the Alocasia Alocasia genus most of which are on genus, Alocasia indica (Roxb.) Schott is the antioxidant property and antitumor and mostly utilized for antioxidant property. Patil et cytotoxic studies. Below is the exhaustive al [16] found significant free radical literature review on the medicinal studies of scavenging activity in the ethyl acetate and n- the Alocasia genus and Table 1 summarizes its butanol fractions of the plant using DPPH (1, 1- medicinal property per species. Diphenyl-2-Picryl-Hydrazyl), superoxide anion radical and nitric oxide tests which may be due to the presence of phenol in its root although 3.1. Antimicrobial Studies in this study IC50 results were not shown and Among the antibacterial studies of Alocasia discussed but was present in the method, it genus is that of Saswati et al [10], were would have been a good quantitative evidence Alocasia decipiens Schott rhizome (roots) of inhibition to oxidation. Another study from methanolic extract gave a 16 mm zone of Islam et al [12] showed strong radical inhibition against Staphylococcus aureus using scavenging activity using its tuber which may the 100% concentration of the extract in a be again due to phenol content and on top of modified filter paper disc diffusion method with this, flavonoid using DPPH test. This study different antibiotic comparisons, this is though seems to address less of antioxidant consistent to the methanolic extract that gave due to the many pharmacologic activity that it a 1 mm zone of inhibition in the study of seems to include compromising detail and Ongpoy [11] moreover with bigger zones using quality of the work. In a much more the dichloromethane fraction at 4 mm with comprehensive study from Pal et al [17], Proteus mirabilis, 3 mm with Pseudomonas DPPH, hydroxyl, nitric oxide and superoxide aeruginosa and 1 mm with Pectobacterium tests were employed in the plants ethanolic carotovorum using the disc diffusion method fraction using its tuber as well that eventually without antibiotic comparison but this time gave a positive result. Tubers though are not with Alocasia sanderiana Bull. leaves. in the the only plant organ studied for antioxidant study of Islam et al [12], disk diffusion method using Alocasia indica (Roxb.) Schott, in the was also employed using Alocasia indica study of Mulla et al [18] the hydroalcoholic (Roxb.) Schott tuber, this study also gave a extract of the plant leaves also possess potent moderate zone of inhibition that ranges from antioxidant activity that may be attributed to 5.8 to 9.8 mm for gram positive and 12.1 mm the presence of flavonoid using DPPH, nitric to 18 mm for gram negative at 250 and 500 oxide and hydroxyl radical tests. ug/disc, the organisms tested were There are also studies for Alocasia macrorrhiza Staphylococcus aureus, Staphylococcus on its antioxidant properties, one is from Patil 26 Romeo C. Ongpoy., /JAASP 2017;6:1 RESEARCH PAPER et al [19] where activity was found to be profiles which are cholesterol and triglyceride present utilizing TBARS (Thiobarbituric Acid in the test animals which may confirm its Reactive Substances) and glutathione tests in traditional use to manage lipidemia and which the plant leaves were used. Rahman et diabetes. al [20] further explored the IC50 value of the plant which is 693 ug/mL using DPPH test of 3.4. Antitumor and Cytotoxic Studies the rhizome. The ground parts were later on found to have more antioxidant activity than Alocasia cucullata (Lour.) G. Don and Alocasia the aerial parts of the plant using solvent macrorrhiza (Linn.) has been studied for fractions of hexane, benzene, toluene, antitumor property. Alocasia cucullata (Lour.) chloroform, diethyl ether, ethyl acetate and G. Don tubers show potent antitumor activity water still using DPPH in the study of Mandal et both in vivo and in vitro in a study conducted al [21] who also studied Alocasia fonicata with by Wei et al [25] where in its in vivo study, the the same findings. There is also a study on cancer expression was down regulated at p-Akt Alocasia decipiens Schott rhizome using its and p-ERK while upregulating Bax/BCl-2 ratio methanolic extract tested through DPPH and FRAP (Ferric Reducing Antioxidant Power) from and caspase 317 activation and in its in vitro study, antiproliferation of G0/G1 phases and Saswati et al [22] that identified IC50 of 14.78 † 0.95 ug/mL which may be due to its phenol cell apoptosis. This study used MTT assay on 5 and flavonoid contents. cell lines to possibly decode the mechanism of action of gastric cancer inhibition previously 3.3. Glycemic and Lipidemic Studies discussed of the