- Syzygium is a genus of flowering plants in the myrtle family, Myrtaceae, comprising of about 1200 species.
Etymology: Genus name derives from the Greek word syzygos, meaning joined or paired, referring to the paired opposite leaves. (Similarly, the Latin word syzygia means joining together or conjunction.) The species epithet is Greek, polyanthum, meaning 'many flowered'.
Syzygium polyanthum is a tree that can grow up to 30 m tall, attain 180 cm in girth size, and with cylindrical or oval tree crown, grayish brown twigs, and gray flaky bark. Crown is cylindrical to oval. Bark is gray and flaky. Leaves are opposite, stalked, thinly leathery, elliptic or lance-shaped, 5–16 cm long by 2.2–7 cm wide, and each has a pointed leaf tip, 1 vein running parallel to the leaf margin, and 6–11 pairs of side veins. Flowers are bisexual, creamy white, turning pink or reddish, faintly fragrant, about 0.8–1.3 cm, and found in up to 10 cm long, flower clusters located at ends of its branches, or axils of its leaves. Fruits are round to flattened round, 0.4–1.2 cm across, fleshy, red to purplish black when ripe, and each containing 1 seed. (2)
- Native to the Philippines.
- Also native to Andaman Is., Borneo, Cambodia, Jawa, Laos, Lesser Sunda Is., Malaya, Myanmar, Nicobar Is., Sumatera, Thailand, Vietnam.
- In primary forests at low and medium elevation, up to 1400 meters.
- Study of stem bark isolated seven compounds: stigmasteril (1), 8-hydroxy-6-methoxy-3-pentylisocoumarin (2), 3,3’-di-O-methylellagic acid (3), methylgallate (4), asiatic acid (5), arjunolic acid (6), and daucosterol (7). (see study below) (3)
- GC-MS analysis of n-hexane, ethyl acetate, and methanol extracts of leaves yielded 21, 27, and 31 peaks, respectively, wit 31.912%, 27.042%, and 22.386% unknown compounds, respectively. Squalene and phytol were among the major compounds in all three extracts. Other identified compounds were hentriacontane, palmitic acid, α-pinene, nerolidol, linalool, α-tocopherol, and ß-tocopherol. (4)
- Leaves and unripe fruits contain carbohydrates, tannins, alkaloids, steroids, terpenoids, and flavonoids; ripe fruits also contain saponins. (6)
- Hydrodistillation of leaves for essential oil yielded aldehydes (ocatanal, cis-4-decanal, 1-decyl aldehyde, capryl aldehyde) and terpenes ( α-pinene, α-caryophyllene, α-humulene, α-copaene, α-selinene, α-zingiberene, ß-caryophyllene, caryophyllene oxide). (6)
- Studies have identified three phenolic compounds in S. polyanthum leaves: caffeic acid, gallic acid, and 4-allyl-1,2-dihydrobenzene (hydoxychavicol). Fractionation of methanol-water extract of leaves have identified three hydroxyl benzoic acid derivatives: 3,4,5-trihydroxy benzoic acid (gallic acid), 4-hydroxy-3-methoxy benzoic acid, and 4-hydro xy-3,5-dimethoxy benzoic acid. (6)
- Vitamin analysis per 100 mg of dry powdered leaves yielded 1.24 mg riboflavin (Vitamin B2), 0.58 mg niacin (Vitamin B3), and 0.40 mg of ascorbic acid (Vitamin C), with the total vitamin content of 2.22 mg. (6)
- Preliminary phytochemical qualitative analysis of methanol extract indicated the presence of tannins, glycosides, flavonoids, alkaloids and saponins. Gas Chromatography-Mass Spectrometry (GC-MS) analysis detected squalene. (see study below) (13)
- An ichthyotoxicity-guided fractionation of leaves isolated two new phloroglucinol-type compounds , namely anthuminoate (1) and anthuminone (2). A photocytotoxicity-guided phytochemical study identified five photosensitizing constituents identified as pheophorbide-a, methyl pheophorbide-a, methyl hydroxypheophorbide-a, pheophorbide-b and hydroxypheophorbide-b. (see study below) (22)
- Methanol extract of leaves isolated three novel compounds [(1) 1-(2,3,5-trihydroxy-4-methylphenyl)hexane-1-one, (2) 1-(2,3,5-trihydroxy methylphenyl)octane-1-one, and (3) (4E)-1-(2,3,5-trihydroxy-4-methylphenyl)decan-1-one and one known compound [(4) 1-(2,3,5-trihydroxy-4-methylphenyl)decan-1-one. (see study below) (28)
- Study showed bay leaves contained 14.81 % (w/w) Fe and 29.42 % vitamin C. Higher levels of Fe, vitamin C and tannins were observed in the ethanol extract of leaves ( 9.39%, 0.15 ppm, and 3,522.63 ppm) compared to methanol extract (5.34 %, 0.09 ppm, and 2,306.84 ppm.
- Study of ethanol extract of bay leaves yielded bioactive compounds with cardioprotective effects: Neophytadiene, squalane, phytol, methyl palmitate, stigmasterol, and 9,12-Octadecanoic acid methyl ester.
(see study below) (37)
- Studies have suggested antioxidant, anti-inflammatory, antidiabetic, cardioprotective, antibacterial, wound healing, nephroprotective, antiproliferative, anthelmintic, antihypertensive, hypolipidemic, neuroprotective, preservative, tyrosinase inhibitory, hypouuricemic properties.
Leaves, roots, bark.
- Fruits and leaves are edible. Fruits, ripe or unripe, have a sweet-sour taste.
- Young leaves have a slightly sour taste. Used as spice in Southeast Asian cuisine. Fresh or dried leaves added to meat, vegetables and rice dishes, curries and stews, or eaten raw as salad.
- In Malaysia, poultice of leaves, roots, and bark applied on skin to relieve itching. (2)
- In Indonesia, leaf infusions and bark extracts used to treat diarrhea.
- Bark and leaves used for abdominal pain.
- Used for treatment of diarrhea, rheumatism, diabetes mellitus, hypertension, skin diseases.
- People in Riau, Sumatra, Indonesia, add leaves into soups and taken for hypertension.
- In North Sumatera, Indonesia, herb is most commonly used by diabetic patients.
- Bark: In the Dutch Indies, bark infusion used to tan fishing nets and dye bamboo mats.
- Wood: Moderately hard to hard, pale to pinkish brown. Used as building material for home construction and furniture making. (2)
• Anti-Inflammatory / Antioxidant / Stem Bark and Root Bark: Study evaluated stem bark and root bark for the anti-inflammatory activity based on inhibition of prostaglandin E2 production in LPS-induced human whole blood and antioxidant activity using DPPH and FRAP assays. The ethyl acetate fraction of root bark showed potent inhibitory activity on production of PGE2 (IC50 3.03 µg/mL). Both parts of S. polyanthum showed high amounts of phenolics and flavonoids. Methanol extract of stem bark exhibited promising DPPH scavenging activity (SC50=2.82 µg/mL) and FRAP activity (7.02 µg/mL of equivalent trolox amount). Stem bark yielded seven compounds. Compounds 1, 5, 6, and 7 exhibited pronounced inhibitory activity of PGE2 production, while compound 4 exhibited antioxidant activity toward DPPH and FRAP. (see constituents above) (3)
• Antioxidant / Antidiabetic / Leaves: Study evaluated the antidiabetic and antioxidant effects of Syzygium polyanthum leaf and Momordica charantia fruit extracts using DPPH and FRAP assays and alpha-amylase and alpha-glucosidase enzyme inhibitory assays. Extracts of Syzygium polyanthum demonstrated better free radical scavenging activity than Momordica charantia. DPPH % inhibition by fresh juice of SP was 64.93, similar to quercetin (p>0.05). FRAP was significantly higher than quercetin (69.05 vs 63.27) (p<0.05). Fresh juice of S. polyanthum demonstrated significant inhibitory actions (p<0.05) against α-amylase (92.21%) and α-glucosidase (96.06%) than acarbose. The fresh juice of S. polyanthum showed superior invitro antioxidant and antidiabetic activities. (5)
• Antibacterial / Cytotoxic / Leaves: Study evaluated the potential antibacterial and cytotoxic effect of S. polyanthum leaves against 4T1 and MCF-7 mammary carcinoma cells and against bacterial causing mastitis in cows. Results showed weak antibacterial activity and cytotoxic effect to mammary carcinoma cells. Further studies are recommended for in vivo testing. (7)
• Antidiabetic / Leaves: In a survey on traditional herbs used by 264 diabetic outpatients in North Sumatera, Indonesia, S. polyanthum was the most commonly used herb in the traditional management of diabetes. Study evaluated various extracts in diabetic and non-diabetic rats and STZ-induced diabetic rats. Metformin- and methanol extract treated group showed significantly reduced blood glucose levels. The methanol extract of leaves showed to be the most effect anti-hyperglycemic preparation. (8)
• Cytotoxicity Testing by Brine Shrimp Lethality Assay (BSLA) / Leaves and Fruits: BSLA is a preliminary assessment assay in evaluating potential toxicity of a plant extract prior to toxicity evaluation in higher animals. The ethanol extract of leaves showed an LC50 (lethal concentration that causes 50% morbidity in total brine shrimp larvae) of more than 1000 µg/mL. An extract is considered nontoxic if the LC50 is more than 500 µg/mL. Results suggest the leaf extract is nontoxic. Safety study on fruits revealed LC50s of >1000 µg/mL for unripe fruits and 747.45 µg/mL for ripe fruits. (6)
• Anti-Inflammatory / Antioxidant / Polycystic Ovary Syndrome (PCOS): Study evaluated the anti-inflammatory and antioxidant potential of S. polyanthum bioactive compounds using in silico approach. Bioactive compounds found and used in the study were deoxyphomalone, NCGC00169066-01, and phloretin. Predicted biologic activity were anti-inflammatory, immunosuppressant, TNF expression inhibitor, immunomodulatory, and HIF1α expression inhibitory. Molecular docking analysis showed deosyphomalone, NCGC00169066-01, and phloretin had inhibition potential against TNF-α and NF-kB, and activation potential against SOD. The anti-inflammatory and antioxidant potential of the bioactive compounds have potential in the treatment of PCOS. (9)
• Antioxidant / Leaves: Study evaluated the antioxidant activities of S. polyanthum leaves extracts using DPPH and ABTS assays. The methanol extract showed highest antioxidant activity on DPPH assay with IC50 of 44.35 mg/mL, and highest activity on ABTS assay among extracts with IC50 of 17.69 mg/mL. (10)
• Cardioprotective in Post-ACS (Acute Coronary Syndrome) / Leaves: Study evaluated the inhibitory effect of bay leaf (Syzygium polyanthum) on matrix metalloproteinases (MMPs) (MMP-9 and MMP-13) inhibitory effect in surgery-induced acute coronary syndrome (ACS) rat model. Results showed bay leaf can reduce overexpression of MMO-13 in surgery-induced ACS rat model. The extract has potential as an adjuvant to prevent cardiovascular adverse event and adverse cardiac remodeling post-ACS. (11)
• Effect on IL-10 Levels in Acute Coronary Syndrome / Leaves: IL-10 is an immunoregulatory cytokine produced by various cells, including activated monocytes, macrophages, and lymphocytes. Study conducted in ACS patients suggests IL-10 has a protective role both in atherogenesis and plaque susceptibility. Study evaluated the effect of bay leaf extract (S. polyanthum) on serum interleukin (IL)-10 levels in the hear of Wistar strain mice model of ACS. Results showed the concentration of IL-10 was significantly greater in the treatment group, suggesting the potential benefit of bay leaf extract in patients with ACS. (12)
• Antihyperglycemic / Leaves: Study evaluated the antihyperglycemic effect of methanol extract (ME) of S. polyanthum leaf and possible mechanisms of action in Sprague Dawley rats. Repeated administration of metformin and three doses of ME (250, 500, 1000 mg/kg) for six days showed significant reduction of fasting blood glucose levels in STZ-induced diabetic rats. Study suggests the antihyperglycemic effect was mediated by inhibition of glucose absorption from the intestine and promotion of glucose uptake by the muscles. (see constituents above) (13)
• Healing of 2nd-Degree Burn Wounds / Leaves: Bay leaf (S. polyanthum) can heal wounds due to contents of essential oils, flavonoids, and saponins. Study compared Simplicia and extract of macerated bay leaf on healing of second-degree burns in vivo. Kruskal Wallis test showed p-value 0.042, p<0.05, a significant difference between dosage botanicals and extracts of leaves healing grade II-A burns. A crude drug preparation, bay leaf extract showed distinction as also significantly affecting burn wound healing. (14)
• Antihyperlipidemic / Inhibition of HMG CoA Reductase Enzyme / Antioxidant / Leaves: Study evaluated the antihyperlipidemic and antioxidant potential of Bay Leaf (S. polyanthum) and its invitro mechanism. Flavonoid concentration of bay leaf extract was 2.852%, and antioxidant activity IC50 was 12.05 µg/mL. In the HMG-CoA reductase inhibitory test, the extract showed IC50 of 22.74 µg/mL. Results suggest strong antioxidant activity with ability to inhibit HMG-CoA reductase enzyme. (15)
• Subchronic Toxicity Testing / Leaves: Study evaluated the subchronic effects of bay leaves extract on body weight, physical changes, and mortality in female Wistar rats on low iron diet, supplemented with 300, 1000, 2000, and 5000 mg/kbw extract for 28 days. Oral administration of the four doses of bay leaves extract showed no observed adverse effects. (16) Study evaluated the subchronic toxicity of ethanol extract of leaves on white Wistar rats using doses of 100, 400, and 1000 mg/kbw. Results showed not toxicity effects on body weight, hematology, creatinine, and SGPT, but fatty liver and necrosis was observed in female rats. (44)
• Teratogenic Testing: Study evaluated the teratogenic potential of S. polyanthum ethanol extract on morphology of fetal mice strain DDY. Extract doses of 0.5, 5, 50, and 500 mg/kbw were given to 30 pregnant female mice orally from 6th to 15th day of gestation. Results showed treatment of ethanol extract during period of organogenesis did not have significant influence on morphology of fetal mice (Mus musculus L.) strain DDY. (17)
• Functional and Sensory Properties as Herbal Tea / Leaves: The leaves can be processed into herbal tea with a simple processing method. Leaves were dried at 40, 50, and 60°C for 24 hours to increase shelf life. A drying temperature of 40°C was selected for highest antioxidant properties. Herbal tea was prepared with brewing at 80, 90, and 100° C for 10, 20, and 30 mins. Result showed lower brewing temperature (80°C) and long brewing time (30 min) could increase functional properties, with highest antioxidant activity (IC50 of 984.07 ppm). Bay leaf tea brewed for 30 mins showed highest
α-glucosidase inhibitory activity of 4704.79 ppm, about 85 times weaker compared to acarbose. Brewing time did not affect the sensory acceptance of the herbal tea with overall hedonic score of 4-5 (slightly like). (18)
• Nephroprotective / Benzene-Induced Renal Toxicity: Study evaluated the ability of ethanol extract of S. polyanthum to prevent kidney damage in benzene-induced toxicity. Results showed extract doses of 400, 600, and 800 mg/kbw reduced levels of urea, creatinine, uric acid, and NGAL, which were significantly different in the group that was only given benzene. (19)
• Cytotoxic / Antiproliferative Effect / Leaves: Study evaluated the cellular mechanisms of Syzygium polyanthum leaves for potential development into commercial herbal product for certain degenerative diseases. The flavonoids extract, which has the lowest IC50 value of 14.84 µg/mL for DPPH assay, was found to have significant cytotoxic effect on both HB4C5 and colon 26 cells. Specific assays for apoptosis using caspase 3-gene expression and annexin-V flow cytometry, supported the cell proliferation inhibition was not due to apoptosis. The crude extract may induce cell cycle arrest of HB4C5 at G1 to S phase, while active compound flavonoid fractions stacked the cell cycle at G2/M phase. Study suggests the flavonoid extracts possess active compounds with antiproliferative effect. (20)
• Hypouricemic / Anti-Gout Potential / Leaves: Study evaluated the effect of bay leaf extract in reducing uric acid levels in male white rats (Rattus novergicus). Results showed bay leaf extract was positive for flavonoid compounds. Kruskal Walis analysis showed a 0.003 p significance value. Study showed bay leaf extract can reduce uric acid levels in male white rats, which was attributed to flavonoid compound contents that can inhibit xanthine oxidase and the formation of uric acid. (21)
• Photocytotoxicity / Leaves: An ichthyotoxicity-guided fractionation of leaves isolated two new phloroglucinol-type compounds, namely anthuminoate (1) and anthuminone (2). A photocytotoxicity-guided phytochemical study identified five photosensitizing constituents identified as pheophorbide-a, methyl pheophorbide-a, methyl hydroxypheophorbide-a, pheophorbide-b and hydroxypheophorbide-b. Inhibition of cell viability ranged from 83.3 to 86.1% at test concentration of 5 µg/mL. Study suggest potential new source in the studies of photocytotoxicity for photodynamic therapy. (22)
• Antidiabetic / Complementary to Metformin / Leaves / Clinical Trial: A previous study showed the extract mixture (EM) of Andrographis paniculata and Syzygium polyanthum leaves had antidiabetic effects on alloxan-induced diabetic rats. This randomized placebo-controlled double-blinded parallel clinical trial examined the benefits of EM of AP and SP leaves in lowering blood glucose with standard antidiabetic treatment using metformin in 54 patients with type 2 diabetic. Phytochemical analysis of the mixture yielded glycosides, terpenoids, alkaloids, flavonoids, saponins, and tannins. Methyl ester of 9-octadecenoic acid and eicosanoic acid were the main constituents of both species. Results showed potential beneficial effects of the EM as complementary medicine alongside conventional treatment of metformin. (23)
• Neuroprotective / Complementary to Metformin / Leaves / Clinical Trial: Benzene is known to cause toxic and carcinogenic effects. Study evaluated the neuroprotective effect of ethanol extract of S. polyanthumm in benzene-induced rats. Results showed the ethanolic extract of S. polyanthum can reduce the number of biomarker interferon-gamma and COX-2 in benzene-induced rats. (24)
• Antidiarrheal / Leaves: Study evaluated the antidiarrheal activity of bay leaves extract in an animal model of castor oil induced diarrhea. Results showed the ethanol extract of bay leaves at 30% concentration exhibited 88% inhibition compared to loperamide-HCl at 89%. (25)
• Natural Preservative for Chicken Meats / Leaves: Study evaluated the potency of infusion of S. polyanthum leaves as preservative of fresh chicken meats. The infusion was prepared by method described in Indonesian Pharmacopeia. Its application as preservative was evaluated based on activity in inhibiting growth of bacteria on the meats and physical observation of the preserved meats. Results showed the infusion at optimum concentration of 10% was capable of inhibiting bacterial growth on chicken meats and extending shelf life up to 3 days at 3-7°C. Flavonoids, tannins, and saponins in the infusion may be responsible for the antibacterial activity and preservative potency. (27)
• Melanogenesis and Tyrosinase Inhibition / Leaves: Study evaluated nine Indonesian medicinal plants for inhibition of melanogenesis and tyrosinase activity in B16 melanoma cells. Three novel compounds [(1) 1-(2,3,5-trihydroxy-4-methylphenyl)hexane-1-one, (2) 1-(2,3,5-trihydroxy methylphenyl)octane-1-one, and (3) (4E)-1-(2,3,5-trihydroxy-4-methylphenyl)decan-1-one and one known compound [(4) 1-(2,3,5-trihydroxy-4-methylphenyl)decan-1-one were isolated from methanol extract of leaves. Results showed that S. polyanthum leaf extract at 25-200 µg/mL decreased melanin formation ca. 20-80% with high cell viability. Compounds 1-4 were active in melanogenesis and tyrosinase inhibition. Compound 3 was most active against tyrosinase activity (83.98 µM). Compounds 1-4 significantly diminished extracellular melanin formation in B16 melanoma cells (>80%), with high cell viability. (28)
• Anti-Inflammatory / and Tyrosinase Inhibition / Leaves: Study evaluated the potency of bay leaves to prevent inflammation and decrease paw edema thickness in Wistar rats induced with Complete Freund's Adjuvant (CFA). Bay leaves extracts were given orally in doses of 100, 300, and 400 mg/kbw. Results showed anti-inflammatory effect. Flavonoids may play a role in inhibiting cytokines proinflammatory synthesis. (29)
• Antihypertensive / Leaves: Study evaluated the effect of combination of celery herb ethanol extract and bay leaf ethanol extract on hypertension in Wistar rats induced by sodium chloride and high fat feed. Results suggest the ethanol extract combination can decrease systolic blood pressure. (30)
• Repellent / Culex quinquefasciatus / Leaves: Complete randomized design study evaluated the potential of bay leaf extract as Culex quinquefasciatus repellent. Results showed the lowest mean of Culex quinquefasciatus which repelled was 83% and the highest was 95.5%. (31)
• Larvicidal Against Aedes aegypti / Leaves: Study evaluated the larvicidal activity of leaf extract of S. polyanthum against Aedes aegypti larvae. Results suggest potential as larvicide. LC50 of salam leaf extract as larvicide to A. aegypti was LC50 of 6576.68 ppm or 0.66%. (32)
• Anthelmintic / Ascaridia galli / Leaves: Study evaluated the potential of ethanolic extract of Indonesian bay leaves as anthelmintic alternative against Ascaridia galli. The leaf extract up to concentration of 14% can damage the cuticle of A. galli. Study suggests potential as anthelmintic against A. galli. (33)
• Cardioprotective in Diabetic Cardiac Apoptosis: Persistent hyperglycemia directly activates cell death pathway that plays a pivotal role in the development of diabetic cardiomyopathy. Study evaluated the cardioprotective effect of S. polyanthum dry extract (300 mg/kbw for 28 days) in STZ-induced diabetic rats. Cardiac apoptosis was analyzed by TdT-mediated dUTP nick end-labeling (TUNEL Assay). Persistent hyperglycemia and cardiac apoptosis was significantly observed in the diabetic rat. Significant blood glucose reduction and lesser concentration of cardiac apoptosis was observed in the extract treated rats. Results suggest S. polyanthum may play a beneficial role in diabetic-associated cardiac apoptosis through its direct effect on blood glucose concentration. (35)
• Cardioprotective / Anti-Inflammatory / Myocardial Infarction Model: In myocardial infarction, inflammatory cytokines including tumor necrosis factor-α play a pivotal role throughout worsening and recovery processes, and its cleavage is controlled by disintegrin and metalloproteinases-17 (ADAM-17). Study evaluate the effect of S. polyanthum extract towards TNF-α and ADAM17 expression in MI rat model. Myocardial infarction was surgically induced by ligation of the left anterior descending artery, and the extract administered via NGT. Results showed anti-inflammatory effect by decreasing ADAM17 expression subsequently lowering TNF-α regulation in the myocardial infarction rat model. (36)
• Cardioprotective / Doxorubicin Toxicity: Chemotherapeutic drug doxorubicin can induce cardiotoxicity. Study evaluated the cardioprotective effect of ethanol extract of bay leaf. Results showed cardioprotective potential. The most effective dose was observed at 500 mg/kbw, with histopathological significant improvements in interstitial edema, wavy fibers hemorrhage, intracellular vacuole, and inflammatory cell infiltration. (see constituents above) (37)
• Nephroprotective / Doxorubicin Toxicity: Doxorubicin can cause nephrotoxic effects that is related to the metabolic conversion of doxorubicin to doxorubicinol. The toxicity is due to interaction with iron and the formation of ROS that damages cell macromolecules. Study evaluated the nephroprotective effects of S. polyanthum in doxorubicin induced male wistar rat. Results showed the ethanol extract possess nephroprotective activity with effective dose of 500 mg/kbw. (38)
• Burn Wound Healing / Leaf Extract Gel: Leaves have been applied to wounds to facilitate healing. Study evaluated the activity of Salam leaf gel for healing of grade 2 burns in white rats. With 15% gel, the average healing was 3.3 days. With 15% and 30% concentrations, histological exam showed thickest granulation tissue. Results suggest leaf extract gel is effective in the healing process of grade 2 burns and has potential as complementary or alternative treatment. (39)
• Antibacterial against Staphylococcus aureus and S. epidermis / Leaves: Staphylococcus aureus and S. epidermis are common causes of nosocomial infections. Study evaluated the antibacterial activity of ethanol extract of Salam leaves against S. aureus and S. epidermis by disk diffusion method. Results showed moderate activity (10.51 mm) at 75% concentration and low activity (3.69 mm) at 100% concentration against S. aureus and S. epidermis, respectively. (40)
• Anti-Plaque Mouthwash Rinse in Fixed Orthodontic Appliance / Leaves: Fixed orthodontic appliance patients have a high risk of increased plaque accumulation in tooth surface. Study evaluated the effect of rinsing with 60% of bay leaf aqueous solution decoction on the accumulation of dental plaque. Chlorhexidine ).2% was used as control. Plaque scoring was done using Orthodontic Plaque Index. Results showed significant different in the plaque index before and after treatment between group rinsing with 60% bay leaf decoction and group rinsing with chlorhexidine (p<00.05). Study suggests 60% bay leaf aqueous decoction can decrease the accumulation of dental plaque in fixed orthodontic appliance patients. (41)
• Effect on Blood Sugar Regulation via GLUT4 Protein Regulation / Leaves: Study evaluated the effect of bay leaf extract on blood sugar levels and the expression of GLUT4 protein in muscle tissue in a study of 30 white rats (Rattus norvegicus) Wistar strains. Treatment with bay leaf extract was able to reduce blood sugars significantly in alloxan-induced white rats by increasing glucose intake in cells and tissues. Metformin drugs or bay leaf extract showed the ability to increase the level of GLUT4 protein. (42)
• Hypolipidemic / Bark: Study evaluated the effect of 70% ethanol extract of Salam bark on the lipid profile of male Wistar rats. The 70% ethanol extract of bark at doses of 0.72 and 1.44 g/200 g bw/day can decrease blood cholesterol, triglycerides and LDL levels (p<-0.05), and at doses of 0.36, 0.72. and 1.44 g/200 g bw/day can increase serum HDL (p<0.05). (43)
- Seeds and capsules in the cybermarket.