 Gen info
- The family Costaceae consists of four genera and about 200 species. The genus Costus is the largest in the family, with about 150 species of mainly tropical distribution. (14)
- The plant is related to the gingers and was once part of the Noninteracting family. However, the Costus species and kin have been reclassified in its own family, Costaceae. (18)
- The use of leaves as a dietary supplement for the treatment of diabetes has earned the catchphrase "a leaf a day keeps diabetes away."
(30)
Botany
Costus igneus is a perennial, upright, spreading plant growing to a height of 2 feet, with the tallest stems falling and lying on the ground. Leaves are simple, alternate, entire, oblong, 4-8 inches long with parallelvenation, spirally arranged around the stems. Large, fleshy, smooth, and dark green leaves have a light purple underside. Flowers are yellow to orange, 1.5 inches in diameter, on cone-like head at the tips of branches. Fruits are green colored, less than 0.5 inch.
Distribution
- Introduced.
- Native to South and Central America.
- Widely cultivated in India for medicinal use.
- Increasing cultivation in the Philippines for medicinal use.
- Ornamental cultivation.
 Constituents
- Leaves are rich in protein, iron, and antioxidant components such as ascorbic acid, α-tocopherol, ß-carotene, terpenoids, steroids, and flavonoids.
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Ethanol extract of leaves yielded tannins, phlobatannins, saponin, flavonoids, terpenoids, and cardiac glycosides. (9)
- Study for essential oil yielded the following major constituents in %: (Stem) hexadecanoic acid (28.3), 9,12-octadecadienoic acid (18.33), dodecanoic acid (5.62), linalyl propanoate (6.03), tetradecanoic acid (4.82), α-eudesmol (3.55), γ-eudesmost (3.21) 4-ethoxy phenol (3.06); (Leaf) hexadecanoic acid (24.51), 2.pentanol (22.41), dodecanoic acid (3.96), ß-ionone (8.69), farnesyl acetone (7.04), α-ionone (8.01; (Rhizome) hexadecanoic acid (25.26), 9,12-octadecadienoic acid (7.74), dodecanoic acid (16.56), tetradecanoic acid (10.20), linalool (8.48), α-terpinol (4.44). (14)
- Proximate analysis yielded 15.3% protein, 120mg iron, 216mg ascorbic acid, 1833 µg ß-carotene, 25 mg α-tocopherol, 400 mmol GSH, 2.1g total phenols, and 1.89 mg/g extract of total flavonoids. (29)
- Phytochemical screening showed the presence of steroids, triterpenoids, alkaloids, tannins, glycosides, saponins, carbohydrates, and proteins. A methanol extract the highest content of phytochemicals.
(30)
 - Sequential screening
of leaves for phytochemical showed it is rich in protein, protein, iron, and antioxidant components such as ascorbic acid, α-tocopherol, ß-carotene, terpenoids, steroids, and flavonoids. (30)
- Qualitative analysis of a leaf extract yielded alkaloids, carbohydrates, saponin, protein, phytosterols, phenolic compounds, flavonoids, and glycosides. Quantitative estimation showed the leaves to have higher content of saponin and total flavonoids, with lesser amounts of phenols and alkaloids.
(34)
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Study reports on the isolation, characterization and quantification of diosgenin from sapogenin extract of Costus igneus rhizome. Diosgenin present in the sapogenin extract was estimated at 0.5%. (36)
- Ethanolic extract of leaves yielded carbohydrates, triterpenoids, alkaloids, proteins, tannins, saponins, flavonoids, and steroids. (see study below)
(37)
- Nutrient composition of dehydrated sample yielded 4.0% moisture, 2.8% fat, 6.3% total ash,
18% protein, 40mg iron, 6.6 mg phosphorus, 5.1mg calcium, 4.5g/100g total phenols, 0.848mg/g total flavonoids, 667µg ß-carotene, 149mg α-tocopherol, 81mg ascorbic acid, 75 m mols glutathione (GSH). (46)
- Proximate analysis of C. igneus cookies (% dry weight): Moisture 7.94%, solids 92.06%, total ash 70.7%, fat 3.75%, fiber 8.03%, protein 3.24%, total carbohydrate content 80.2%. Ascorbic acid was 4.2µg/g, ß-carotene 1.49µ/g and total phenolic content was 5.44mg/g. Cookie antioxidant activity using DPPH radical scavenging assay showed 62.3%. (see study below) (45)
- Study of ethanol leaf extract yielded tannins, flavonoids, steroids, phenols, and alkaloids, whereas silver nanoparticles leaf extract yielded tannins, saponins, alkaloids, and steroids. Saponins and terpenoids were absent in the ethanol extract, and flavonoids, terpenoids, and phenols were absent in the NPs. (48)
- GC-MS analysis yielded of ethanol leaf extract yielded 2-nonynoic acid,
carbamodithioic acid, tetraborane, cyclohexanone, 9-hexadecanoic acid, 11,14-eicosanoic acid, octadecanoic acid, 1,2-benzenedicarboxylic acid, 9-hexadecenoic acid, tetradecanoic acid, diosgenin acetate, d-xylitol, cyclotrisiloxane, 1-benzopyrylium, and benzoic acid. (48)
Properties
- Studies have suggest antimicrobial, antidiabetic, hypolipidemic, antiproliferative, antioxidant, anti-inflammatory, hepatoprotective. anticancer properties.
Parts used
Leaves, roots, stem.
 Uses
Edibility
- Leaves are edible, chewed.
- Leaves used for making tea.
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Flowers are edible, sweet.
Folkloric
- In the Philippines, becoming increasingly popular as an antidiabetic herbal medicine.
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In Siddha medicine, used for diabetes; leaves chewed twice daily, or dried powder of leaves taken 1/2 to 1 gram twice daily.
- Used by tribal people of Kolli hills of Tamilnadu for diabetes.
(14)
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Leaves consumed as fresh, dried and powder leaf forms.
- In Mizoram, India, decoction of leaves and roots used to reduce blood sugar. (22)
- In west Sikkim, India, leave s used for treatment of diabetes, skin diseases, asthma, bronchitis, fever, and intestinal worm disease. (26)
- In Mexico, infusion of aerial parts used for treatment of renal disorders. (14)
 Studies
• Anti-Hyperglycemic / Dexamethasone Induced Hyperglycemia / Leaves: Study evaluated the effect of Costus igneus leaves on dexamethasone-induced hyperglycemia in male Wistar rats showed reduction in fasting and postprandial blood sugar levels. 250 mg and 500 mg/kg/day of powdered leaves was comparable to Glibenclamide 500. (3)
• Antidiabetic / Acute Oral Toxicity Study / Leaves: Study evaluated the antidiabetic activity of C. igneus in alloxan induced diabetic albino rats. The ethanolic extract showed significant (p<0.001) antidiabetic activity. (4)
• Effect of Prediabetes and Diabetes in Neonatal STZ Rats: Study evaluated the effect of pre-treatment and post-treatment with isolated fraction of C. igneus on prediabetes and diabetes in neonatal streptozotocin induced T2DM. Treatment with CIF is beneficial in diabetic rats and can reduce the changes of progression of pre-diabetes into T2DM. Effect may be due to increase in peripheral utilization of glucose and insulin mimetic effect. (5)
• Acute Oral Toxicity Study: Acute oral toxicity studies of CIF fraction of chloroform extract showed no abnormal or toxic symptoms in mice treated with 5, 50, 500, 2000 mg/kg. LD 50 value is above 2 g/kg. (5)
• Anti-Proliferative / Apoptotic / Leaves: Study evaluated the anti-proliferative and apoptotic potential of ME of Costus igneus on in vitro MCF-7 Breast cancer cell line. Results showed reduction of tumor size without affecting the normal cells. (6)
• Antidiabetic / Hypolipidemic / Rhizomes: Study evaluated the antihyperglycemic and hypolipidemic activities of methanol extract of rhizomes in STZ induced diabetic albino rats. Results showed significant (p<0.05) decrease in FBS, TC, TG, LDL, and VLDL levels, with significant (p<0.05) increase in HDL levels. (7)
• Antimicrobial / Rhizome: Study evaluated the rhizome extract of three Costus species (C. speciosus, C. pictus, and C. igneus) for antimicrobial activity. The rhizome extract of the three species inhibited the growth of all the test fungi. The C. igneus extract showed higher activity against S. aureus, followed by P. aeruginosa, E. coli, and B subtilis. (8)
• Amylase Inhibitory Activity / Leaves: Study evaluated the amylase inhibitory activity of methanol leaf extract of C. igneus by Chromogenic DNSA assay. The extract showed dose dependent α-amylase inhibition of 65.48, 35.72, and 3.57% at 500, 250, and 100 µg concentration. (10)
• Silver Nanoparticles / Antidiabetic: Study reports on the simple and cost-effective synthesis of silver nanoparticles using C. igneus extract. The C. igneus mediated nanoparticles showed high antidiabetic activity and maximum amylase inhibition concentration of 87% at 100 µg. The AgNPs showed good antidiabetic activity than the plant extracts. (11)
• Hepatoprotective / Paracetamol Induced Liver Damage: Study evaluated the hepatoprotective activity of C. igneus in paracetamol induced hepatic damage. Administration of C. igneus extract prior to acetaminophen effectively (p<0.05) prevented the induction of damage by acetaminophen. The 400 mg/kg dose of C. igneus was comparable to the standard drug silymarin. (12)
•
Potential Anticancer Source: Study evaluated the cytotoxicity activities of crude ethanolic extracts from Chaemaecostus subsessilis and C. cuspidatus and six fractions against a panel of six human cancer cell lineages (HL60, Jurkat, MDA-MB231, MCF-7, HCT, THP-1). Cytotoxic effects in the HL60, Jurkat and THP-1 lineages were mediated via an apoptotic mechanism. (13)
• Antidiabetic / Antioxidant / Antimicrobial
/ Leaves: Study of an aqueous leaf extract of C. cuspidatus showed antidiabetic against streptozotocin induced diabetic mice. Antioxidant activity was evaluated using DPPH, superoxide anion scavenging activity, hydroxyl radical scavenging activity and reducing power assays. Antibacterial activity was tested against S. aureus, B. subtilis, E. coli and antifungal activity against A. flavus and C. albicans. (16)
•
Gold Nanoparticles / Antidiabetic / Leaves: Study reports on the green synthesis of gold nanoparticles using insulin plant Chamaecostus cuspidatus leaf powder extract. The gold nanoparticles exhibited 50% inhibition of free radicals. Treatment of diabetic mice with the gold nanoparticles restored blood glucose, glycogen, and insulin level. (17)
• Toxicity Studies: Acute oral toxicity studies of aqueous extract of C. pictus at various doses from 5, 10, 20, and 40 g/kg body weight. None of the extract doses produced mortality or any behavioral disorders. Administration of 1 g/kbw per day for 30 days, likewise, produced no mortality or behavioral effects. An ethanolic extract of leaves from 50 mg/kbw up to 5000 mg/kbw showed no mortality or significant toxicity. (15)
• Antihyperglycemic / Insulin Plant Leaves and Curcuma longa Rhizome: Study evaluated the antihyperglycemic activity of insulin plant leaves and unprocessed rhizome of Haridra (Curcuma longa) in rabbits with diabetes induced by dexamethasone, Results showed extremely significant(p=0.0001 decrease in blood glucose levels in both groups. Unprocessed haridra showed significant )p=0.0109) decrease in blood glucose level as compared to insulin plant leaves. (18)
• Antifungal / Saponins / Rhizomes: Study evaluated the antifungal activity of crude ethanol extracts of leaves, stems, and rhizomes of Chamaecostus cuspidatus against Candida and Trichophyton species. Only the rhizomes showed antifungal activity and had no activity against bacteria (S. aureus and E. coli). The hexane fraction from the rhizome extract showed the best antifungal effect. Three known saponins were isolated from the fraction, of which two (dioscin and aferoside A) showed good antifungal activity. Fungicidal activity caused significant changes in the morphology of the fungal cells and showed anti-Candida albicans biofilm activity. (20)
• Hypoglycemic Action of Insulin-Like Protein / Toxicity Study: An earlier study reported an orally active insulin-like protein from Costus igneus with potent hypoglycemic effect in STZ-induced diabetic Swiss mice. This study elucidated the hypoglycemic mechanism of the ILP. Results showed the orally active ILP acts via an insulin signaling pathway. The ILP did not show toxicity in normal and diabetic Swiss mice. (21)
• Antimicrobial / Steroid / Stem: Study of ethanol extract of Costus igneus stem isolated a steroid compound. The compound was tested for antimicrobial activity against S. aureus, E. coli, and C. albicans. Results showed good antibacterial and antifungal activity. (23)
• Comparative Hypoglycemic and Hypolipidemic Activity: Study compared the therapeutic effects of C. igneus methanolic and aqueous extracts against hyperglycemia and hyperlipidemia in alloxan induced diabetic rats. The methanol extract exhibited higher activity than the aqueous extract. (24)
• Silver Nanoparticles / Antimicrobial / Leaves: Study reports on the synthesis of antibacterial nanoparticles using a leaf broth of Costus igneus. The silver nanoparticles showed enhanced antibacterial activity against well known pathogenic strains viz. Streptococcus sp., Pseudomonas aeruginosa, Staphylococcus sp., Proteus sp., as well as fungi Penicillium sp., Mucor sp., Candida albicans, Aspergillus sp. (25)
• Chlorogenic Acid Mediated Silver Nanoparticles / Free Radical Scavenging / Anti-Inflammatory: Study evaluated the antioxidant and anti-inflammatory properties of chlorogenic acid medicated silver nanoparticles. Results showed significant anti-inflammatory and anti-oxidation activity of chlorogenic mediated AgNPs. which proportionately increased with increasing concentration. (27)
• Hypoglycemic Carbon Dots: Study evaluated the hypoglycemic bioactivity of novel eco-friendly carbon dots derived from Costus igneus. The carbon dots were synthesized from by a simple hydrothermal treatment at relatively low temperature. The carbon dots inhibited alpha-amylase in a concentration dependent manner, suggesting C. igneus has antidiabetic property. (28)
• Effect of leaves on Blood Glucose Levels of Diabetic Patients: A Cross-Sectional Study: A cross0awxtional study in diabetic patients evaluated the effect of consumption of insulin plant on glycemic control. Retrospective data was was collected from diabetic patients who consumed the leaves of the insulin plant. in fasting and postprandial blood sugar levels in all the patients who consume the leaves. (31)
• Anti-Urolithic / Calcium / Leaves: Study evaluated a methanolic extract of leaves of Costus igneus for in-vitro anti-urolithic activity. The percentage dissolution of calcium oxalate in the presence of the extract in semi-permeable egg membrane was studied and compared with standard drug cystone. Percentage dissolution was 86.12% for the extract and 79.34% for cystone. Results suggest potential for use in treatment of urolithiasis and can be added to polyherbal formulations. (32)
• Antioxidant / Cytotoxic / Anticancer / Leaves: Study evaluated the antioxidant and cytotoxic potential of different leaf extracts A hexane extract showed highest Antioxidant activity was evaluated using FRAP, ABTS, . DPPH and reducing power assay while cytotoxicity was evaluated using MTT assay on breast cancer cell line MCF-7 (Michigan Cancer Foundation). In FRAP assay, the acetone extract showed highest antioxidant activity, the hexane extract in ABTS showed highest radical scavenging activity, and the acetone extract in DPPH assay. The acetone leaf extract at concentration of 150µg/ml showed highest cytotoxic activity on the cancer cell line with cell viability of 65.51%. Results suggest efficient antioxidant and cytotoxic activity and could be a safe and cost-effective potential for biologic applications. (33)
• Antiangiogenic / Non-Teratogenic / Leaves: Study evaluated the anti-angiogenic potential of crude ethanolic extract of Costus igneus through chorioallantoic membrane (CAM) vascularity and teratogenicity assays in mallard duck (Anas platyrhynchos). Teratogenicity assay showed statistically insignificant gross morphological abnormalities. The extracted crude crude ethanolic substance did not contain components that can significantly inhibit angiogenesis. Also, results reveal insulin plant has no teratogenic effect. (34)
• Insulin-Like Protein (ILP): Insulin-like protein (ILP) is purified from Costus igneus. The ILP showed cross-reactivity with murine anti-insulin antibodies, hence was purified by affinity chromatography using anti-insulin antibodies.. The ILP was structurally different but functionally similar to insulin. The ILP significantly decreased blood glucose in OGTT given orally to normal and diabetic mice. The ILP is a novel protein with oral hypoglycemic activity. (35)
• Cytotoxicity / Hepatocellular Carcinoma / Leaves: Study evaluated the in vitro anticancer activity of ethanolic extract of Costus igneus leaves against hepatocellular carcinoma (HepG2) cells. %h4 concentration required for 50% viability *IC50) was calculated at 62.5µg/mL. Results showed cytotoxic activity against liver cancer cells. (see constituents above) (37)
• ZnO Nanoparticles / Antibacterial / Leaves: Study reports on the synthesis of high-purity zinc oxide nanoparticles from Costus igneus leaves using different solvents. The hot water extract-based green synthesis process yielded higher purity (99.89%) and smaller particle size (94nm) than other solvents. The NPs showed antibacterial activity against Gram-positive S. aureus and S. epidermis and Gram-negative E. coli and K. pneumoniae. Results suggest the green-synthesized high-purity NPs has potential for therapeutic and cosmetic applications. (38)
• Salicylic Acid as Plant Elicitor to Increase Productivity: New approaches are being developed to protect the plant source and to enhance productivity in terms of phytochemicals to balance supply and demand. Flavonoid diglycosides and sapogenins are mostly responsible for the anti-diabetic activity. Due to over exploration, alternative methods are developed to protect the plant in their natural habitat. Elicitors are compounds that stimulate plant defense pathways. Release of secondary metabolites are triggered by elicitors. This study evaluated the application of Salicylic acid (SA) in different concentrations as elicitor. Results showed SA enhances the quantity of desired phytopharmaceuticals, which play an essential role in plant defensive pathways. (39)
• Flavonoids / Hypoglycemic Impact / Rhizome: Study isolated and quantified flavonoids from ethanol extract of Costus igneus rhizome and the impact of CiREE on hypoglycemic effect in STZ-induced diabetic rats. Quercetin (Rf-0.72. 0.794%) and kaempferol (Rf-0.35, 4.2%) were quantified by HPTLC. Results showed that treatment with CiREE pf rats with pretreatment abnormalities ( increased elevated blood glucose, serum TC, TG, LDL, VLDL and decreased HDL, glycogen and insulin levels) resulted in reversal back to normal. Histopathological and electron microscopy study of the pancreas showed increase in number of ß-cells and insulin granules. Results showed the CiREE has potent antidiabetic effect comparable to that of standard reference drug glibenclamide. (40)
• Antidiabetic / Toxicity Study / Leaves: Study evaluated acute toxicity and antidiabetic effect of C. igneus extracts (acetone, hexane, hot water) on STZ-induced diabetic wistar albino rats. Acute toxicity testing showed various tested extracts did not show any mortality at all tested concentrations. The hexane extract of leaves caused significant (p<0.001) reduction of blood sugar level. There was also significant reduction in BUN. Significant reduction of creatinine was observed at 400mg/kg in all three leaf extracts. Results were equipotent to glibenclamide. Results suggest a safe and cost-effective herbal drug for the treatment of diabetes. (41)
• Anti-Urolithic / Calcium Oxalate / Stems: Study evaluated the effects of aqueous and ethanolic extracts of C. igneus stem on calcium oxalate urolithiasis in male albino wistar rats. Results concluded that treatment with aqueous and ethanolic extract had an inhibitory effect on calcium oxalate urolithiasis. Lupeol and stigmasterol were confirmed by HPTLC technique. (42)
• Anti-Diabetic / Increased Insulin and GLUT3 Expression / Leaves: Study evaluated lost ß-cell regeneration in diabetes and successfully differentiated human haematopoietic stem cells (HSCs) from functional ß-like cells. Costus igneus leaf extract is known to exhibit anti-diabetic properties by lowering blood glucose level in mice models. This study evaluated the effect of C. igneus on differentiated ß-like cells. The Ci leaf extract exhibited anti-diabetic property elevated glucokinase activity which catalyzes the rate-limiting step of glucose catabolism in ß-like cells and acts as a sensor for insulin production while decreasing the glucose-6-phosphatase activity. Results showed enhanced IBS and GLUT2 gene expression and elevated glucokinase activity in ß-like cells differentiated from HSCs. The extract has potential for use in the treatment of diabetes. (43)
• Antibacterial / Roots: Study evaluated acetone, chloroform, and methanol extracts of roots for antimicrobial activity against four Gram-negative bacteria viz Pseudomonas aeruginosa, Klebsiella pneumonia, Salmonella sp. and Proteus vulgaris. K. pneumonia was found most susceptible to both growth regulators IBA and IAA derived roots, with 25 mm zone of clearance, which was almost equal to commercial antibiotic gentamicin. (44)
• Antidiabetic Insulin Plant Cookies / Leaves: Study reports on the formulation of a nutritionally rich cookie with Costus igneus leaf extract and evaluates the effect of cookie consumption on decreasing blood sugar levels in 30 type 2 diabetic patients. Proximate analysis showed the cookies contain high amounts of secondary metabolites including antioxidant compounds. The cookies showed good
α-amylase inhibitory activity. Results showed significant reduction of blood glucose levels. There was a one unit drop in HbA1C. Results showed good antidiabetic and antioxidant activities and potential as a therapeutic and functional food source for the treatment of obesity and diabetes. (see constituents above) (45)
• Ipil-ipil Seed Gum as Co-Encapsulating Agent for Powdered Insulin Plant: Study evaluated the use of Leucaena leucocephala (Ipil-ipil) as a source of co-encapsulating material for controlled drug delivery release of C. cuspidatus leaves. Galactomannan, the main component of isolated seed gum, can be used as substitute for effective controlled drug release. FTIR study showed successful incorporation of the powdered leaves inside the encapsulating material. Ridges and pores were present on the surface of the capsules for immediate disintegration and hydration. Results suggest Leucaena leucocephala seed gum is a potential candidate as co-encapsulating material for effective, targeted, and controlled delivery of C. cuspidatus leaf powder for maximum antidiabetic benefits. (49)
• ZnO Nanoparticles / Anticancer against MCF-7 and A549 Cell Lines / Leaves: Study reports on the synthesis of ZnO nanoparticles used leaves of C. cuspidatus. MTT assay evaluated the invivo cytotoxicity of the ZnONPs against lung epithelial and breast cancer cell lines. Results showed cytotoxicity against MCF-7 and A549 cell lines with IC50s of 30 µg/mL and 37 µg/mL, respectively. (50)
Availability
- Cultivated.
- Increasing availability in herbal gardens.
- Powdered leaves, rhizomes, capsules and teas in the cybermarket.
- FDA issued Advisory No. 2020-1465 II Public Health Warning against purchase and consumption of five unregistered Insulin Plant Products and Supplements: (1) ECOGEN Insulin Plus (Chamaecostus cuspidatus) 100% Herbal Capsules 500 and 100 mg, (2) Unbranded Costus igneus Herbal Food Supplement 500 mg capsules, (3) Unbranded Plant Tea Leaves Powder C. igneus (Raw, Pure, Air Dry) 45 gms, (4) RLB Organics Insulin Powder 100g (5) Unbranded Insulin Plant Herbal Capsule 500 mg.
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