A Pharmacognostical & Phyto Pharmacological Review of Terminalia Catappa: An Updated Retrospective Study

The Ayurvedic herb Terminalia catappa is famous for its many names, including "deshi badam," tropical almond, Indian almond, Malabar almond, and Indian almond ^[1]. Originally from Madagascar, Asia, & Pacific, Terminalia catappa Linn is a Combretaceae family member ^[2]. Genus name comes with Latin word terminus, which is "very end of the branch". This is because the leaves are located at very end of the branch.  Terminalia catappa is a coastal plant that thrives in tropical and subtropical climates ^[4]. As a food and medicine, medicinal almonds having long history of usage in treating and prevention of many metabolic and neurological disorders.  In traditional medicine, almonds have a role in promoting health ^[5]. Most often, fallen leaf of Terminalia catappa Linn are boiled or made into beverage called tea. ^[6]

Taxonomic classification of terminalia catappa: ^[7]

Morphological Characteristics: ^[8]

Size & Structure: Standing 15–25 meters tall, this deciduous tree typically has a trunk diameter of 1–1.5 meters and is commonly buttressed at base.

Branches: Branches are separated in tiers and lean slightly upward; as they age, they lengthen & droop at ends.

Bark: Greyish-brown, rougher as per aging.

Leaves: Alternate, obovate, spirally grouped at branch ends, 15–36cm in length, 8–24cm broad, dark green top and lighter below, leathery & lustrous; sheds in crimson, scarlet, purple, or yellow when ripe.

Flowers: Flowers are tiny, greenish-white, and somewhat stinky. They don't have any petals but ten or twelve noticeable stamens. They grow in narrow spikes (15–25 cm long) in spaces between leaves. From February to May, blooms are usually male, although there are a few that are hermaphroditic.

Fruit: A drupe that is hard, spherical, flattened, and shaped like an egg (up to 7 cm long) with 2 ridges and no wings; when mature, it changes colour to yellow or reddish.

Seed: Shaped like a cylindrical prism, it has an inside fleshy pericarp and a tough, fibrous husk that contains oil.

Vernacular Names:

Common name: Indian Almond Marathi & Hindi: Jangle badam, Vadumai, Nattuvadumai, and Ketapa in Malayalam Tapasataruvu in Telugu. Kannada: Tavasa, Naatibaadaami, Kaadubaadaami, and Naadubaadaami, Bengali: Badam, Oriya: Desiyobadamo, Gujarati: Badamalili, Sanskrit: Inguda, Ingudee, Taapasataru ^[9]

Habit:

The overall growth form and structure of Terminalia catappa are referred to as its habit. It’s massive deciduous tree which grows till 15 to 25 meters in height. When young, the tree has a characteristic pagoda-like look due to its upright, straight trunk, which is frequently buttressed at the base, and its horizontally tiering branches. The branches droop more at the tips as it gets older. As it ages, the greyish-brown bark becomes rougher. The tree has a dense canopy because of the huge, leathery leaves that are spirally huddled at the terminals of the branches. ^[10]

Habitat:

Terminalia catappa inhabits tropical and subtropical environments, mostly along the shore. It grows well in lowland tropical forests, which are frequently found close to water bodies like lagoons and estuaries; urban and cultivated landscapes, including parks, roadsides, and gardens, because of its shade-providing canopy; sandy beaches, riverbanks, and coastal plains, where it can withstand salt spray and saline soils; and tropical climates with warm temperatures and 1,000–3,500 mm of annual rainfall. ^[11]

Cultivation:

Terminalia catappa, or tropical almond, is tropical tree cultivated for shade, edible seeds, and medicinal uses. It thrives in warm, coastal climates with well-drained, acidic to neutral soils and full sun. Seeds are the primary method of propagation; soaking in hot water at 70°C for five minutes increases germination to 80% in eighteen days. Plant 3–5 meters apart during the wet season, water regularly for the first 1–2 years, and apply balanced fertilizer annually. Prune to shape the canopy and monitor for fungal diseases. Fruits ripen in 1–3 years, with seeds harvested in March–April for high oil content (up to 56.38%). The tree tolerates drought and salt but may require clean up due to falling leaves and fruits, and its spread should be managed in sensitive areas. ^[12]

Phyto Chemical Constituents:

Chemical nature:

An assortment of phenols, including terflavins A and B, tergallagin, and catappanin etc, are found. Quercetin, rutin, and isovitexin are all chemicals that are classified as flavonoids.  This group includes compounds such as ursolic acid, squalene, asiatic acid, 2 & 23-trihydroxyurs-12-en-28-oic acid (DHUA).  Vitamins C and E, along with carotenoids like β-carotene, are essential.

The part from which they originate:

• Bark : In addition to catappanin, there are two phenol carboxylic acids, two phenolic glycoside gallates, seven ellagic tannins, and four flavan-3-ols [7,21,25]. Glycoside, volatile oils, saponin, steroids, arjunolic acid, two triterpenes, two triterpenoid saponins, and sitosterol 3-O-β-D-glucopyranoside are all present.
• Seed: Proteins, ash, fat, carbohydrates, water etc, and a variety of acids.

• Leaves: β-tocopherol, punicalagin and its derivatives, p-coumaric acid, gallic acid, saponins, phytosterols, ash, protein, glucose, moisture, oil painting oil, carbohydrates, and oil painting oil.
• Fruit: β- carotene, cyanidin-3-glucoside, ellagic acid, brevifolin carboxylic acid, pentosans, glucose, and tannin. ^{[13, 14]}

Pharmacological Uses:

Terminalia catappa is widely studied in pre-clinical research and possesses a wide variety of pharmacological activities. Such bioactive chemicals as flavonoids, tannins, triterpenoids and others are present in large quantities in its leaves, bark, seeds and fruits conferring medicinal properties. The plant’s anti-oxidant, anti-inflammatory, anti-bacterial, and anti-microbial properties make it a good remedy fair diverse assortment of ailments and health conditions having swelling as the underlying factor. By pathways of enzyme inhibition, free radical scavenging, and gene expression regulation, it also exerts anti-aging, anti-diabetic, anti-cancer activities. Additional research related to T. catappa has involved anti-atherosclerotic, anti-parasitic, anti-hepatoprotectant, wound-healing, anti-HIV, and cardioprotectant aspects. Its immune regulatory and erythropoetic modulating activity also support its therapeutical flexibility. Terminalia catappa is considered as a natural source of compound for the prevention and treatment of various chronic as well as infectious diseases owing to their various pharmacological activity. ^[15]

Research Findings

Anti – bacterial activity:

Researchers have looked at the antimicrobial capabilities of ethanoic and water-based extracts of Terminalia catappa bark and leaves against a small number of harmful bacteria.  Tests against four different bacteria - Escherichia coli, Bacillus subtilis, Staphylococcus aureus, and Enterobacter aerogenes—were conducted to determine antibacterial properties of ethanoic and aqueous extracts of Terminalia catappa bark and leaves.  To assess the antibacterial activity, the agar disc diffusion technique was used.  Comparing the extracts' activities to those of the commonly used antibiotic Ciprofloxacin, inhibition zone technique was used to evaluate their efficacy.  The results showed that out of the three concentrations tested (100, 200, and 300  µg/ml), 300 µg/ml had the best impact. ^{[16, 17, 18]}

Anti – aging activity:

For this study, researchers used a hydrophilic T. catappa extract, which protects erythrocytes against 2,2'-Azobis AAPH-induced haemolysis and demonstrates DPPH-free radical scavenging activity.  Activities of elastase is not decreased by T.catappa, while collagenase activity is inhibited in a dose-dependent manner (ranging from 82.3% to 101.0%).  In addition, at concentrations of 25µg/mL and 50µg/mL, T.catappa inhibits the production of MMP-1, MMP-9, and MMP-3 proteins, respectively.  Furthermore, T. catappa promotes the synthesis of type I procollagen.  In order to decrease MMP-1, -3, and -9 production, T.catappa inhibited phosphorylation of ERK, JNK, and p38.  This means it may slow down the ageing process. ^[19]

Hypoglycemic Activity:

Main aim of research was to ascertain if Terminalia catappa L. leaves had any anti-diabetic benefits on rats given streptozotocin( STZ). Blood samples were analysed for biochemical labels after diabetic rats were given two different tablets of T.catappa leaf extract (300 and 500 mg/ kg) in an ethanoic form. The issues of herbal remedies were varied with those of glibenclamide, a common drug. Anti-diabetic effects of the ethanol except (500 mg/kg) were observed through alterations in glucose 6-phosphatase, fructose 1,6-bisphosphatase, urea, uric acid, and creatinine levels, as well as an increase in insulin levels.  Hence, results of present research suggest that patients with diabetes might profit from using T.catappa leaves as supplement in order to alleviate some of symptoms associated with their condition. ^{[20, 21, 22]}

Anti-Microbial Activity:

Two nutraceutical plants, Terminalia catappa L. and Colocasia esculenta L. were studied for their antimicrobial, antioxidant, and synergistic qualities. Methanolic extract of T. catappa shown good antibacterial action in the current study both on its own and when combined with conventional antibiotics, it demonstrated good synergistic activity. ^{[23, 24, 25, 26]}

Anti-Helmintic Activity:

A study evaluating the anthelmintic potential of Terminalia catappa leaf extract used an in vitro bioassay with L₃ larvae of T. colubriformis, C. curticei, and H. contortus. Larvae were incubated with the extract at 20°C for 3 and 5 hours, and motility was assessed using an inverted microscope. After 3 hours, the reduction in motility was 70%, 63%, and 73% respectively, increasing to 77%, 67%, and 80% after 5 hours. Controls using PBS( Phosphate buffer solution) and distilled water showed no significant reduction. These findings suggest T. catappa leaves possess promising anthelmintic properties. ^[27]

Anti-Tumor Activity:

There are 354.02 mg/g of phenolic and 51.67mg/g of flavonoid content in the ethanoic extract of T. catappa.  Both the peritoneal cell count and the life duration are increased by T. catappa extract at 2 different doses, 50mg/kg and 200mg/kg.  At 200mg/kg, it also considerably reduces the solid tumour mass compared to mice with EAC tumours.  Mice treated with the extract show normal levels of RBC, WBC, haemoglobin, and protein.  In contrast to its negative effects on lipid peroxidation and lowered glutathione levels, T.catappa has a dramatic effect on SOD & CAT levels.  The presence of phenolic and flavonoid components may explain T.catappa's antioxidant defence and its anticancer action, which is shown by changes in LPO levels. ^[28-37]

Chemopreventive Effect:

A study examined the chemo preventive effects of Terminalia catappa (TC) on AOM-induced colon carcinogenesis in 36 male F344 rats. Five groups of rats were created: AOM alone was given to Group 1, AOM + 0.02% or 0.1% TC was given to Groups 2 and 3, 0.1% TC was given to Group 4 without AOM, and Group 5 was left untreated. For two weeks, AOM was given at a rate of 20 mg/kg each week, and T.catappa feeding started one week earlier. Following five weeks, in comparison to the AOM-only group, T.catappa at both dosages considerably reduced PCNA labelling index, ACF, and BCACs in colon.  It seems that T.catappa inhibits the formation of ACF and BCAC, which would explain its strong short-term chemo preventive action against biomarkers of colon cancer. ^[38]

Free Radical Scavenging and Anti-Oxidant Activity:

In comparison to extracts produced by sonicating T. catappa leaves for 20 or 60 minutes, as well as a control, the 40-minute sonication method yielded significantly higher polyphenolic levels.  After 40 minutes of sonication, the antioxidant tests show that the vitamin C equivalent values of the sonicated extract are much greater compared to previous sonication and control intervals.  It is possible that the polyphenolic content is responsible for this action.  Multiple assays, including DPPH, nitric oxide, reducing power, and H₂O₂ tests, have shown that T. catappa has dose-dependent antioxidant activity. ^[39-43]

Anti-Oxidant Activity:

In order to determine methanolic acid's antioxidant activity, three separate assays were conducted: DPPH radical scavenging, oxidative cell death, and linoleic acid oxidation.  Plants growing near subtropical coastlines have been utilised in harvesting leaves from 39 different species.  In every system tested, 2 extracts from Terminalia catappa and Excoecaria agallocha shown very high levels of activity.  HPLC investigation also found same antioxidant in the extracts, & chemical called ellagic acid was isolated. ^[44]

Ace Inhibitory Activity:

Angiotensin converting enzyme (ACE) inhibition was utilised to evaluate potential antihypertensive efficiency of Brazilian plants in vitro.  In all, forty-four plants belonging to thirty-one families were analysed.  Because of their common usage as diuretics and anti-hypertensives, these herbs were chosen.  There was a notable decrease in ACE activity in Terminalia catappa. ^[45]

Anti-Parasitic and Anti-Fungal Activity:

The dried leaves of the Indian almond plant were ground into powder and mixed with water.  Various quantities of this solution are utilised in assessing activity against tilapia pathogens.  Results showed that at 800 ppm, trichodina, a kind of fish ectoparasite, were eradicated.  At a concentration of 0.5mg/ml, Indian almond leaves inhibited the development of two different Aeromonas hydrophilia strains.  In addition, fungal infection in tilapia eggs may be reduced with this treatment.  To find out if this solution is harmful to tilapia and to determine active components of Indian almond for treating fish diseases, researchers are conducting studies. ^[46]

Anti-Inflammatory Activity:

Ursolic acid (1), 23-trihydroxyurs-12-en-28-oic acid (2), which were extracted from the chloroform fraction and used in a bioassay-oriented fractionation technique, showed potent anti-inflammatory effects.  In both acute and chronic contexts, the anti-inflammatory activity of an ethanoic extract of Terminalia catappa leaves was tested utilising 12-O-TPA-induced ear oedema.  The anti-inflammatory action of T. catappa leaves is likely caused by triterpenic acids 1 and 2, according to the results. ^{[47, 48]}

Erythropoietic Enhancing Activity& Modulatory Activity:

By dramatically increasing foetal haemoglobin (HbF) production in both EPO-dependent and EPO-independent erythroid progenitor stem cells, the distilled water active fraction of TCDWF shows promising promise as a new medicinal treatment for sickle cell anaemia.  A dual function in boosting erythropoiesis and regulating cell survival may be attributed to TCDWF, which enhances erythroid lineage commitment, demonstrates selective cytoprotective effects, and differently controls caspase 3 activity.  These results show that TCDWF has great potential as a drug candidate for HbF-inducing treatments. ^{[49, 50]}

Toxicology:

The crude aqueous extract of T. catappa (0.5 g/kg, 1.0 g/kg, and 3.0 g/kg) was found to be both primary (by lethal occurrence) and secondary harmful over 14-day treatment period. During the trial time, no fatality is seen in the rats. Additionally, the rats' dietary behaviour is normal, and no anomalies in their physiological characteristics have been found. ^[51]

Wound Healing:

A wound is defined as an area where the cellular and functional capability of living tissues is lost or disrupted.  The advancement of synthetic antimicrobial medications for wound healing was hindered by drug toxicity and resistance.  More beneficial alternatives for wound healing may be available from a variety of plants with strong pharmacological characteristics.  According to Khan et al., using T. catappa ointment on a wound may reduce its area by 97% compared to a control group that received 81% of the usual treatment and betadine ointment.  The fact that T. catappa ointment speeds up the process of epithelization suggests that the bark extracts do a good job of healing wounds. ^[52]

Anti-Plasmodial Activity:

The chloroquine-sensitive (3D7), Dd2, and multidrug-resistant isolates were successfully decreased by methanol extracts of T. catappa leaves.  From 5.03 to 9.76 µg/mL, the half-maximal inhibitory concentration (IC??) was measured.  With selectivity indices (SIs) ranging from 40 to 80, the extracts effectively suppressed parasites while causing almost little harm to human cells.  The liver enzymes of the mice that were treated did not show any significant negative effects either. ^[53]

Hepato-Protective Activity:

A hepatoprotective activity against both D-GalN & CCl4-induced acute liver damage was shown in the present research by TCCE, which inhibits ALT and AST activities and changes liver shape.  Based on the findings, two triterpenoids—ursolic acid and asiatic acid—may have a dose-dependent ability to protect liver mitochondria from Ca2+-induced swelling of mitochondria and scavenge superoxide anions and hydroxyl radicals. ^{[54, 54, 56]}

Anti-Atherosclerotic & Anti-Hyperlipidemic Activity:

The fruit of T. catappa showed inhibitory effects on atherosclerosis, hyperlipidaemia, and hypolipidemia in an in vivo model of the disease.  The results showed that the T. catappa fruit extracts had anti-atherogenic and antihyperlipidemic effects when used with an atherogenic diet. This was supported by the fact that the CRI and AI reduced, while the CPI (Cell Proliferation Index) rose.  Lipid profiles, enzyme biomarkers, histopathology, cardio protection, and atherogenic indices were all improved after extract administration. ^[57]

Anti-HIV Activity:

About 2 million people die each year from HIV infection, which destroys immune cells and poses a substantial therapeutic challenge due to drug resistance.  As a result, there is a growing emphasis on studying compounds originating from plants in order to create anti-HIV medications.  Natural product-based therapies for HIV/AIDS are still in the clinical testing phase, despite a mountain of data on the virus.  Despite plants' promising anti-HIV capabilities, complex extracts remain difficult to isolate their active ingredients.  Advancements like real-time time-of-flight mass spectrometry provide help, even if they still need additional optimisation.  Terminalia catappa has important phytochemicals that have shown anti-HIV activity. ^[58]

Aphrodisiac Activity:

In this study, rats were given Terminalia catappa Linn. seeds soaked in 1% methyl cellulose to investigate whether they had any aphrodisiac effects.  Oral administration of 1,500 or 3,000 mg/kg SS or vehicle to male rats was followed by observation of their sexual conduct three hours later with an open-minded female.  A separate group of rats were given SS or a vehicle orally for seven consecutive days.  They were paired up with a pro-oestrous female for the night on days 1, 4, and 7 of therapy, & day 7 post treatment, to evaluate their sexual behaviour and fertility.  The aphrodisiac qualities of T. catappa seed kernel may be useful in treating sexual insufficiency, including premature ejaculation. ^[59]

Haematological Activity:

Terminalia catappa nut (TCN) n-hexane extract is investigated in this research for its effects on several haematological parameters, oxidative stress markers, and bone/spleen histology in a Wistar rat model of benzene-induced leukaemia.  Terminalia catappa nut extract may be useful as an adjuvant therapy agent due to its anti-leukemic, haemopoietic, antioxidant, and organ-protective effects in benzene-induced leukaemia in Wistar rats. ^[60]

Anti-Depressant Activity:

This study details physicochemical characterisation of Terminalia Catappa leaf extracts and their antidepressant effects.  The in vivo antidepressant properties of Terminalia Catappa Linn.  Despair Swim test was utilised to ascertain the leaves, using a standard consisting of two extracts containing 200 mg/kg of imipramine (15 mg/kg orally). Period of immobility was significantly reduced on days 8 and 15 of trial due to concentration. ^[61]

Nociceptive Activity:

The anti-nociceptive effects of pulverised activated carbon from Terminalia catappa was investigated in this study as instance of Results of this study indicate that analgesic activity of activated charcoal is linked with its multifaceted mechanism that is characterized by adsorption, anti-inflammatory, antioxidant, and modulation of neurotransmitter activity. Because of such properties, activated charcoal is an effective and cost-effective option to conventional analgesics. ^{[62, 63]}

Genotoxicity:

The objective of this study was to prove that the T. catappa extracts are antimutagenic and anticarcinogenic agents. Moreover, extracts at various concentrations decreased MMS toxicity 11.6–40.30% and in vitro it decreased sister chromatid exchange and increased the replication index. In vivo, the clastogeny reduction is effective between 19.70% and 40.90%. Their reducing capacity is dose and time dependent. ^[64]

Gastro Protective Activity:

FrAq from Terminalia catappa leaves with potent anti-Helicobacter pylori activity should be effective prophylactic and therapeutic agents against both acute and chronic gastric ulcer. The ulcer healing of this fraction by inhibition of MMP-9 and MMP-2 activities and NO pathway is the underlying mechanism of trivial gastro-protection. ^[65]