 Gen info
- Syzygium is a genus of flowering plants belonging to the myrtle family, Myrtaceae. The genus comprises about 1200 species.
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Syzygium myrtifolium, the red lip or kerat oil, is a species of flowering plant in the family Myrtaceae. (2)
- Etymology: The genus Syzygium derives from the Greek word syzygos, meaning "joined", alluding to the opposite paired leaves. The species epithet myrtifolium means myrtle-leaved, describing the plant's foliar shape and texture resembling the leaves of Myrtus. (3)
Botany
• Growth form: A tree with a dense bushy crown, up to 20 m tall. Foliage: Opposite, stalked leaves have leaf blades that are elliptic to lanceolate, about 7.5 cm long and 2.5 cm wide. Young leaves emerge reddish, turning red-brown then green. Flowers: Powderpuff-like flowers are cream to white in color, borne on a branched inflorescence, up to 4 cm long. Fruit: Spherical to ellipsoid fruits are dark purple or black berries, about 9 mm wide. (3)
 Distribution
- Native to the Philippines.
- In forest ridges up to 900 m.
- Also native to Bangladesh, Borneo, Jawa, Malaya, Myanmar, Sumatera, Thailand. (1)
Properties
- Studies suggested antioxidant, antimicrobial, antiviral, anti-inflammatory, anticancer, anti-diarrheal, antispasmodic, α-glucosidase inhibitory, antidiabetic, antidermatophytic, cholesterol lowering, toxicity, immunomodulatory, antimutagenic properties.
 Constituents
- Phytochemical screening of various leaf extracts yielded alkaloids, anthraquinones, flavonoids, phenolics, saponins, tannins, and triterpenoids. (see study below) (4)
- GC-MS analysis for leaf essential oil revealed a total of 43 constituents representing 96.99% of total EO. The EO was characterized by sesquiterpene incorporate alcohols (34.99%) with δ -cadinol (29.53%), caryophyllene oxide (26.25%), and cyclocolorenone (7.7%) as major constituents. (see study below) (6)
- GC-MS analysis of leaves detected 15 compounds with 1,2,3-benzenetriol (37.80%) and caryophyllene (27.49%) as dominant compounds. (see study below) (7)
- Study of leaves isolated a flavonoid, luteolin.
Phytochemical screening of ethanol extract of leaves showed presence of flavonoid, quinone, saponin, tannin, triterpenoid, with absence of alkaloid. (16)
Parts used
Leaves.
 Uses
Edibility
- Fruit is dark red to reddish purple becoming black when fully ripe. No report found on human consumption; however, fruits of many members of the genus are edible, and fruits of this species are eaten by birds.
Folkloric
- No reported folkloric medicinal use in the Philippines.
- In Malaysia, used as remedy for stomach pain.
Others
- Landscaping: Used as landscaping tree, hedge, or shrub due to its colorful young leaves, amenability for pruning (topiary), and for its fragrant flowers. (2)
Studies
• Antimicrobial / Antiviral / Antioxidant / Leaves: Study of various leaf extract of S. myrtifolium for antioxidant activity showed ethyl acetate, ethanol, methanol, and water extracts to have significantly higher (p<0.05) oxygen radical absorbance capacity and ferric reducing antioxidant power than hexane and chloroform extracts. All extracts exhibited stronger inhibitory activity against four tested species of years (MIC 0.02 - 0,31 mg/mL) than against six tested species of bacteria (MIC0.16 - 1.25 mg/mL). The ethanol extract exhibited highest protection of Vero cells (viability >70%) from cytopathic effect of Chikungunya virus while the ethyl acetate extract showed significant replication inhibitory activity against the virus (p<0.001) using replicon-enhanced green fluorescent protein reporter system. (4)
• Acute Toxicity Test / Leaves: Study evaluated the LD50 (lethal dose 50) and acute toxicity of ethanol extract of Syzygium myrtifolium leaves in white mice. Results showed an LD50 of 1995 mg/kbw (moderately toxic). Observed toxic effects included white lesions in the lungs, blackened liver, organ swelling, and fluid accumulation in the abdominal cavity and thorax. (5)
• Anti-Inflammatory / Anti-Cancer / Leaf Essential Oil: Study evaluated the chemical composition, antioxidant, cytotoxicity, and anti-inflammatory activities of Syzygium myrtifolium leaf essential oil. Antioxidant activity of leaf EO against DPPH and ABTS assays showed IC50s of 215 and 116 µg/mL respectively. In vitro cytotoxic effect of EO against HCT-116 and Ps-1 cell lines by MTT assay showed IC50s of 59.9 and 47.5 µg/mL respectively. At concentration of 25µg/mL, the EO showed potential anti-inflammatory activity in lipopolysaccharide-activated RAW 264.7 macrophages by inhibiting nitric oxide (NO) production. Results suggest the leaf EO as a rich source of bioactive constituents, which needs further studies for anti-infllammatory and anti-cancer drug therapies. (see constituents above) (6)
• Effect on Lymphocyte Count and Spleen Index / Leaves: Study evaluated the effect of Pucuk merah (S. myrtifolium) leaves on lymphocyte count and spleen index of Balb/C mice (Mus musculus) using extract doses of 0.127, 0.510, and 0.765 mg/gbw. Results showed low dose (0.510 mg/gbw or less) decreased lymphocyte count in mice, which increased with high dose (0.765 mg/gbw). Spleen index of extract-treated mice did not correlate with the lymphocyte count. (7)
• Antidiarrheal / Antispasmodic / Leaves: Study evaluated the toxicological potential, antidiarrheal, and antispasmodic activities of betulinic acid, dimethyl cardamonin (DC) and standardized non-formulated and nano-formulated ethanol and supercritical fluid extracts from leaves of S. myrtifolium. Standardized extracts produced no invivo toxicity. Both extracts and standardized extracts (SE) showed dose-dependent antidiarrheal activity. DC and SEs showed antispasmodic activity on isolated guinea pig ileum. Compared with hyoscine-N-butylbromide, DC and SEs produced significant, potent antagonizing activity in ileum contractions induced with acetylcholine. (8)
• α-Glucosidase Inhibitory Activity/ Avicularin and 4-O-Methyl Gallic Acid / Leaves: Study evaluated the effect of seven species of Syzygium against α-glucosidase enzyme. Syzygium myrtifolium exhibited the most significant effect. Avicularin and 4-O-methyl gallic acid were isolated from ethyl acetate fraction of S. myrtifolium with IC50s of 17.05 µg/mL and 25.19 µg/mL, respectively. Results suggest S. myrtifolium can be used as dietary supplement to manage hyperglycemia. (9)
• Effect on Liver Sinusoid Appearance / Leaves: Study evaluated the effect of ethanol extract of S. myrtifolium leaves on histopathological structure of the liver. Extract at doses of 2000 mg/kbw and 5000 mg/kbw were given Sprague-Dawley white rats. Histopathological observations found extensive dilation of the hepatic sinusoids in the 2000 and 5000 groups. There were significant differences in control and treatment groups, with no significant difference between treatment groups. Results suggest the ethanol extracts of leaves at 2000 and 5000 mg/kbw doses have an effect on appearance of dilated liver sinusoids. (10)
• Antidermatophytic / Leaves: Study evaluated the the antidermatophytic activity of 48 extracts obtained from medicinal plants. Methanol and water extracts of leaves of Syzygium myrtifolium was highly active (MFC <0.1 mg/ml) with high selectivity index (SI>2.8) against reference strains of Trichophyton rubrum and T. interdigitale, and most of the clinical isolates of T. tonsurans. (11)
• Hypocholesterolemic Effect / Leaves: Study evaluated the effect of extract of red shoot leaves (S. myrtifolium) on decreasing total cholesterol in male Wistar strain white rats using doses of 200, 250, and 300 mg/kbw. Results showed cholesterol lowering effect with potential efficacy in the 300 mg/kbw treatment group, with significant value of 0.647. (12)
• Angiotensin-Converting Enzyme Inhibitory: In a study of ethanol extract of four plants, Syzygium myrtifolium showed ACE inhibition activity with IC50 151.2 ppm. The IC50 of Captopril with ACE inhibition activity is 11.1 ppm. (13)
• Toxicity to Liver and Kidney / Leaves: Study evaluated the toxic effects of ethanol extract of red shoot leaves to the histopathological picture of liver and kidneys of mice (Mus musculus). Doses of 500, 1000, 2000, and 4000 mg/kbw were used. Histological observations showed that doses of 500-4000 mg/kbw caused changes in the liver and kidney cells. Liver showed congestion, sinusoid dilation, mononuclear cell infiltration, and inflammation in the liver. The kidney showed necrotic cells in the proximal tubule, infiltration of inflammatory cell. Results suggest toxic effect of ethanol extract of S. myrtifolium to liver and kidney in mice. (14)
• Immunomodulatory / Leaves: Research has isolated a flavonoid compound with anti-inflammatory benefits and immunomodulatory potential. Study evaluated the immunomodulatory effect of S. myrtifolium. Results showed red tip leaves ethanol extract exhibited an immunostimulatory effect against phagocytosis activity, total and differential leucocyte count, antibody titer value, and delayed-type hypersensitivity. (15)
• Antimutagenic in Cyclophosphamide-Induced Mice: Study evaluated the antimutagenic effects of ethanol extract of S. myrtifolium in cyclophosphamide-induced mice. Extract doses of 50-400 mg/kbw demonstrated antimutagenic effect by inhibiting formation of micronucleus. The hematocrit value increased compared to control. Results suggest the ethanol extract of S. myrtifolium has antimutagenic activity that may increase the normal cell number in cyclophosphamide-induced mice. (17)
• Effect on Filariasis Vector Mortality / Leaves: The use of synthetic larvicides for control of Culex sp. is harmful to environment and human health. Study evaluated the effect of ethanol and water extracts of S. myrtifolium leaves on larval mortality. Treatment of ethanol and water extracts showed significant effect on mortality of Culex sp. larvae. LC50s of ethanol and aqueous extracts were 1659 and 2053.7 ppm respectively. Results suggest effect on mortality of Culex sp. larvae, but not yet effective as biolarvicide. (18)
• Subchronic Toxicity on Liver and Kidney Function / Leaves: Study evaluated the subchronic toxicity of S. myrtifolium ethanolic leaves extract on kidney and liver function of test animal after 60 days of test preparation. Results showed doses of 300, 600, and 900 mg/kbw did not significantly affect the activity of SGOT, SGPT, and serum creatinine levels (p<0.05). Microscopically, at doses of 600 and 900 mg/kbw there was significant difference on percentage damage to glomerulus of right and left kidneys. On qualitative microscopic exam, there were abnormal changes in the sinusoids and hepatocyte cells, and increase in percentage of central vein damage. Results suggest, the ethanol extract of leaves was safe for white mice at dose of 300 mg/kbw, but doses of 600 and 900 mg/kbw caused toxic effect on the kidneys and liver compared to control. (19)
• Acute Toxicity Study of Single Dose
Liver Function / Leaves: Study evaluated a single dose of S. myrtifolium for toxic effect on SGOT and SGPT enzyme levels in Sprague Dawley male white rats (Rattus norvegicus) using test doses of 5, 50, 300, and 2000 mg/kbw and observed for 14 days. The LD50 (lethal dose) was >5000 mg/kbw based on OECD guideline No 423 with 0-1 death in rats at dose of 5000 mg/kbw. (20)
• Leukotriene A4 Hydrolaste Receptor Inhibitors / Anticancer Potential: Study aimed to find active compounds in S. myrtifolium leaves with anticancer activities by inhibiting protein leukotriene A4 hydrolase. Molecular docking methods were used to predict activity and affinity between ligand-proteins. Docking results revealed four active compounds from the leaves: namely bis (2-ethylhexyl) hexanedioate, 3-octadecyne, 1- octadecene, and (2E,6E)-farnesol have a lower docking score compared to bestatin; therefore, these four compounds have the potential to inhibit leukotriene A4 hydrolase receptors and can be candidates for colorectal anticancer compounds. (21)
• Antibacterial Flavonoids: Alanine racemase and transglycosylase are essential proteins for peptidoglycan membrane synthesis in bacteria and an alternative target for antibacterial performance. Study identified six flavonoid compounds in S. myrtifolium with antibacterial activity. In-silico study was conducted for modeling flavonoids - protein complexes. Results showed five flavonoids inhibited alanine racemase and transglycosylase, and the peptidoglycane membrane synthesis in bacteria may be inferred. (22)
Availability
Wild-crafted. |
