Ukufunwa Kwemithi Emisha Okuthakazelisayo

Ngumlobeli We-Phaphama! e-Brithani

Injoloba, ukhokho, ukotini, neziqedanhlungu kufana ngani? Konke kungatholakala ezitshalweni. Ngalé kokwenza ushukela nomoya-mpilo ngenqubo ye-photosynthesis, izitshalo eziluhlaza zibuye zikhiqize ingxubevange engavamile yezinto zisebenzisa ezinye izakhi eziyisisekelo zamakhemikhali. Lamakhemikhali ayizakhi yiwo anikeza isitshalo ngasinye izici ezisehlukanisa kwezinye.

UKUHLABA kwekhakhasi, ukunambitheka okuhlabahlosile kwe-apula, nephunga elimtoti lembali ye-rose konke kubangelwa inhlanganisela yamakhemikhali akhiqizwa izitshalo ngokwazo. Ngakho, lokho okungase kubonakale kuwumkhiqizo owodwa eqinisweni kusuke kuyinhlanganisela eyinkimbinkimbi kakhulu.

Izimboni Zemvelo Zamakhemikhali

Cabanga ngephunga eliphawulekayo likakhokho. Bewazi yini ukuthi izazi zesayensi kuze kube manje sezithole amakhemikhali angu-84 ahlukahlukene ahwamukayo akha leliphunga elikhethekile? Okuqukethwe izinhlamvu zikakhokho kuyinkimbinkimbi kakhulu, futhi eminyakeni yamuva kuye kwenziwa umzamo omkhulu wokuthola ezikuqukethe. Futhi lokhu kumane nje kusewumkhiqizo wemvelo owodwa kuphela.

I-cholesterol ingamafutha, mhlawumbe aziwa kakhulu ngokuhlobana kwawo nesifo senhliziyo kubantu. Kodwa, ezitshalweni ezithile iyisiqalo sokwenza iqembu elibalulekile lamakhemikhali abizwa ngokuthi ama-steroid. Ama-steroid ahlanganisa u-vitamin D, ama-hormone (njenge-cortisone), nemithi enjenge-betamethasone evikela ukungenwa izifo. I-diosgenin, eyi-steroid esetshenziswa ekukhiqizweni kwamaphilisi okuvimba inzalo, ikhiqizwa uhlobo oluthile lwezitshalo ze-yam yasendle. Ngakolunye uhlangothi, i-cortisone yenziwa nge-hecogenin, okuyi-steroid ekhishwa enhlameni yamacembe e-sisal ngemva kokwenziwa kwezindophi. Iningi lezidakamizwa ezintsha namuhla lathathwa ezitshalweni.

Izitshalo Nomuntu

Nakuba ukusebenzisa kwabantu izidakamizwa zokwenziwa kuyintuthuko yesimanje yezokwelapha, izinto ezikhishwe ezitshalweni bezilokhu zisetshenziswa njengamakhambi okugula okuvamile izinkulungwane zeminyaka. Imibhalo egciniwe yase-Asiriya ichaza ukusetshenziswa kwe-anemone evamile ekudambiseni ubuhlungu. Futhi ama-papyrus aseGibithe ezokwelapha angezikhathi zawoFaro embula ukusetshenziswa okubanzi kwezitshalo zokwelapha.

I-World Health Organization inombhalo ogciniwe wokusetshenziswa kwezitshalo zokwelapha ezingu-20 000 emhlabeni wonke. EBrithani iyodwa alinganiselwa ku-6 000 kuya ku-7 000 amathani amakhambi asetshenziswa njezithako zemikhiqizo engu-5 500 ehlukahlukene, futhi kuthiwa e-United States, cishe ngaphezu kwengxenye yayo yonke imithi yodokotela ithathwe ezitshalweni.

Ukuthola Imithi Emisha

Njengoba kunezinhlobo eziningi zezitshalo ezingaba ngu-250 000 ezaziwayo emhlabeni wonke, ngasinye sinamakhemikhali akhethekile, ososayensi bahlala befuna izindlela zokuthola imithi enosizo. Enye yezindlela ezisobala iwukucwaninga indlela abantu abelapha ngayo izifo besebenzisa izitshalo ezimila endaweni yakubo.

Ukutholakala kwe-cocaine kwaqala ngokuphawuleka kokuthi ukuhlafuna amacembe e-coca kwakuqeda umuzwa wendlala futhi kudambisa ukukhathala kwezinzwa. Ngokuthola i-molecule ye-cocaine nangokushintsha isimo sayo, izazi zamakhemikhali zenza umuthi osetshenziselwa ukuqeda ubuhlungu endaweni ethile kuphela. Uma udokotela wamazinyo ekujova ukuze ingxenye yomhlathi wakho ibe “ndikindiki” ukuze ungabuzwa ubuhlungu, kungenzeka ukuthi usuke uzuza kulokho kucwaninga.

Ukwaziswa okuningi okunosizo mayelana nokusetshenziswa kwezitshalo kusagcinwe emitatsheni yezindawo ezicwaninga ngezitshalo. Izazi zesayensi ezachitha iminyaka emine zicwaninga ngezitshalo eziyizigidi ezingu-2,5 e-Gray Herbarium and Arnold Arboretum yaseHarvard University zakwazi ukuthola izinhlobo ezingaphezu kuka-5 000 ezazingazange ngaphambili zithathwe njengezingaba usizo kwezemithi.

Omunye umgudu wokucwaninga uqhathanisa amakhemikhali akhona ezitshalweni. Uma uhlobo oluthile lunezakhi eziwusizo, izinhlobo ezihlobene nalo zingaba usizo. Lapho ukucwaninga ngesihlahla sasenyakatho Australia, i-chestnut yase-Moreton Bay, kuveza i-castanospermine, ewubuthi obubulala amagciwane, izazi zezitshalo ezazifuna izihlahla ezihlobene naso zasikisela ukuba kucwaningwe ngesihlahla saseNingizimu Melika okuthiwa i-Alexa.

Ukucwaninga Ngemithi Yokulwa Nomdlavuza

Ngezinye izikhathi izimpawu zingadukisa bese kuvela imiphumela engalindelekile. Ngokwesibonelo, kwakuthiwa umuthi okhishwe kuyi-periwinkle yase-Madagascar ungaselapha isifo sikashukela. Izisebenzi zocwaningo zaseCanada zaqala ukuwuhlola, kodwa zamangala lapho lomuthi ovela kuyi-periwinkle ucindezela isimiso somzimba sokuzivikela ngokunciphisa ukukhiqizwa kwamangqamuzana amhlophe egazi. Lokhu kwanikeza odokotela umqondo wokuzama lomuthi ekwelapheni i-leukemia, umdlavuza wamangqamuzana amhlophe egazi.

Ekugcineni kwatholakala imithi engu-90, emibili yayo eyaziwa ngokuthi i-vincristine ne-vinblastine, eye yabonakala iwusizo kwezokwelapha. Iba khona esitshalweni ngezilinganiso ezincane kangangokuthi kudingeka cishe ithani elilodwa lezitshalo ukuze kukhiqizwe amagremu amabili e-vincristine. Namuhla lemithi neminye evela kuyo isetshenziswa emhlabeni wonke ezindleleni zokwelapha ngamakhemikhali ekwelapheni i-leukemia ebantwaneni.

Ekupheleni kwawo-1950, i-U.S. National Cancer Institute yaqala uhlelo lokuhlunga lweminyaka engu-25, okwathi phakathi nalo kwahlolwa izithako ezingu-114 000 ezivela ezinhlotsheni ezingu-40 000 zezitshalo ukuze kubonakale ukusebenza kwazo ekumelaneni nezigaxa zomdlavuza. Ezingu-4 500 zaveza imiphumela ephawulekayo, okwakusadingeka ihlolwe ngokwengeziwe. Kodwa uDkt. W. C. Evans ongumeluleki kweze-pharmacognosy uyaphawula: “Kubonakala sengathi empeleni ngeke zitholakale izidakamizwa ezingozifo-zonke zokulwa nomdlavuza,” ngenxa yalokucwaninga, nakuba kubalulekile nje. Umdlavuza uhlukahlukene kakhulu, futhi kwakusetshenziswe amangqamuzana omdlavuza okhula ngokushesha ambalwa kuphela kulokhu kucwaninga.

Imithi Emisha Evela Ezitshalweni Ezindala

Izitshalo ezaziwayo zisiza abacwaningi ukuba bacabangisise. Ngokwesibonelo, ijinja isisetshenziswa njengomuthi wokuvimbela ukucanuzela kwenhliziyo, osebenza kahle kakhulu ekudambiseni isiyezi esibangelwa izinto ezihambayo.a Okubaluleke nangaphezulu, ijinja ingasebenza kahle ekuletheni ubungcono kwabaphethwe isifo sasezindaweni ezishisayo okuthiwa i-schistosomiasis (isichenene). Ukuhlolwa kwezingane zesikole ezigulayo eNigeria, kusetshenziswa amaphilisi empushana yejinja, kuye kwanqamula ukuvela kwegazi emchameni wazo futhi kwanciphisa isilinganiso samaqanda e-schistosome.

Abacwaningi abakenzi lutho ekuhloleni umkhakha wezitshalo ukuze kutholakale eminye imithi. Ngisho nezitshalo esezaziwa ngesilinganiso esithile nazo zisenezimfihlo eziningi. I-licorice manje isifunwa kakhulu ngenxa yokuthi amakhemikhali akuyo asebenza njengesivikelo ekungenweni izifo futhi imithi eyakhiwe ngawo ingaletha ubungcono kubantu abaphethwe yisifo sokuqaqamba kwamalunga. Izazi zesayensi zisacwaninga uphizi wasengadini ukuze kutholakale imiphumela yokulwa nokukhunta namagciwane.

Ukucekelwa phansi kwezinhlobonhlobo zezitshalo okungenangqondo ezindaweni ezithile zomhlaba, ngaphambi kokuba lezozitshalo zibhalwe phansi, kubonisa ukuthi ukucwaningwa kwemithi emisha kufanele kuqhubeke ngesivinini esikhulu. Ukuhlaziywa ngokucophelela kwamakhemikhali asezitshalweni nokwakheka kwezici zawo zofuzo kuyinto okufanele ize kuqala, ngisho nokwezitshalo esezaziwa. Kodwa kusenempicabadala eyodwa okusamelwe ixazululwe: Lamakhemikhali angajwayelekile azisiza ngani izitshalo ngokwazo? Ngokwesibonelo, kungani isitshalo okuthiwa i-purslane sinesilinganiso esiphakeme kangaka se-noradrenaline, okuyi-hormone okutholakale ukuthi ibalulekile enhlalakahleni yabantu?

Ngempela, ulwazi lwethu ngobunkimbinkimbi bempilo yezitshalo lulinganiselwe kakhulu. Kodwa lokho esikwaziyo kukhomba emklamweni omkhulu, okuletha udumo kuMklami Omkhulu.

[Umbhalo waphansi]

[Isithombe ekhasini 24]

Ijinja isetshenziselwa ukwelapha isiyezi esibangelwa izinto ezihambayo